Language Server Protocol Specification - 3.15

This document describes the upcoming 3.15.x version of the language server protocol. An implementation for node of the 3.15.x version of the protocol can be found here.

Note: edits to this specification can be made via a pull request against this markdown document.

Base Protocol

The base protocol consists of a header and a content part (comparable to HTTP). The header and content part are separated by a ‘\r\n’.

Header Part

The header part consists of header fields. Each header field is comprised of a name and a value, separated by ‘: ‘ (a colon and a space). Each header field is terminated by ‘\r\n’. Considering the last header field and the overall header itself are each terminated with ‘\r\n’, and that at least one header is mandatory, this means that two ‘\r\n’ sequences always immediately precede the content part of a message.

Currently the following header fields are supported:

Header Field Name Value Type Description
Content-Length number The length of the content part in bytes. This header is required.
Content-Type string The mime type of the content part. Defaults to application/vscode-jsonrpc; charset=utf-8

The header part is encoded using the ‘ascii’ encoding. This includes the ‘\r\n’ separating the header and content part.

Content Part

Contains the actual content of the message. The content part of a message uses JSON-RPC to describe requests, responses and notifications. The content part is encoded using the charset provided in the Content-Type field. It defaults to utf-8, which is the only encoding supported right now. If a server or client receives a header with a different encoding then utf-8 it should respond with an error.

(Prior versions of the protocol used the string constant utf8 which is not a correct encoding constant according to specification.) For backwards compatibility it is highly recommended that a client and a server treats the string utf8 as utf-8.

Example:

Content-Length: ...\r\n
\r\n
{
	"jsonrpc": "2.0",
	"id": 1,
	"method": "textDocument/didOpen",
	"params": {
		...
	}
}

Base Protocol JSON structures

The following TypeScript definitions describe the base JSON-RPC protocol:

Abstract Message

A general message as defined by JSON-RPC. The language server protocol always uses “2.0” as the jsonrpc version.

interface Message {
	jsonrpc: string;
}

Request Message

A request message to describe a request between the client and the server. Every processed request must send a response back to the sender of the request.

interface RequestMessage extends Message {

	/**
	 * The request id.
	 */
	id: number | string;

	/**
	 * The method to be invoked.
	 */
	method: string;

	/**
	 * The method's params.
	 */
	params?: Array<any> | object;
}

Response Message

A Response Message sent as a result of a request. If a request doesn’t provide a result value the receiver of a request still needs to return a response message to conform to the JSON RPC specification. The result property of the ResponseMessage should be set to null in this case to signal a successful request.

interface ResponseMessage extends Message {
	/**
	 * The request id.
	 */
	id: number | string | null;

	/**
	 * The result of a request. This member is REQUIRED on success.
	 * This member MUST NOT exist if there was an error invoking the method.
	 */
	result?: string | number | boolean | object | null;

	/**
	 * The error object in case a request fails.
	 */
	error?: ResponseError<any>;
}

interface ResponseError<D> {
	/**
	 * A number indicating the error type that occurred.
	 */
	code: number;

	/**
	 * A string providing a short description of the error.
	 */
	message: string;

	/**
	 * A Primitive or Structured value that contains additional
	 * information about the error. Can be omitted.
	 */
	data?: D;
}

export namespace ErrorCodes {
	// Defined by JSON RPC
	export const ParseError: number = -32700;
	export const InvalidRequest: number = -32600;
	export const MethodNotFound: number = -32601;
	export const InvalidParams: number = -32602;
	export const InternalError: number = -32603;
	export const serverErrorStart: number = -32099;
	export const serverErrorEnd: number = -32000;
	export const ServerNotInitialized: number = -32002;
	export const UnknownErrorCode: number = -32001;

	// Defined by the protocol.
	export const RequestCancelled: number = -32800;
	export const ContentModified: number = -32801;
}

Notification Message

A notification message. A processed notification message must not send a response back. They work like events.

interface NotificationMessage extends Message {
	/**
	 * The method to be invoked.
	 */
	method: string;

	/**
	 * The notification's params.
	 */
	params?: Array<any> | object;
}

$ Notifications and Requests

Notification and requests whose methods start with ‘$/’ are messages which are protocol implementation dependent and might not be implementable in all clients or servers. For example if the server implementation uses a single threaded synchronous programming language then there is little a server can do to react to a ‘$/cancelRequest’ notification. If a server or client receives notifications starting with ‘$/’ it is free to ignore the notification. If a server or client receives a requests starting with ‘$/’ it must error the request with error code MethodNotFound (e.g. -32601).

Cancellation Support (:arrow_right: :arrow_left:)

The base protocol offers support for request cancellation. To cancel a request, a notification message with the following properties is sent:

Notification:

  • method: ‘$/cancelRequest’
  • params: CancelParams defined as follows:
interface CancelParams {
	/**
	 * The request id to cancel.
	 */
	id: number | string;
}

A request that got canceled still needs to return from the server and send a response back. It can not be left open / hanging. This is in line with the JSON RPC protocol that requires that every request sends a response back. In addition it allows for returning partial results on cancel. If the request returns an error response on cancellation it is advised to set the error code to ErrorCodes.RequestCancelled.

Progress Support (:arrow_right: :arrow_left:)

Since version 3.15.0

The base protocol offers also support to report progress in a generic fashion. This mechanism can be used to report any kind of progress including work done progress (usually used to report progress in the user interface using a progress bar) and partial result progress to support streaming of results.

A progress notification has the following properties:

Notification:

  • method: ‘$/progress’
  • params: ProgressParams defined as follows:
type ProgressToken = number | string;
interface ProgressParams<T> {
	/**
	 * The progress token provided by the client or server.
	 */
	token: ProgressToken;

	/**
	 * The progress data.
	 */
	value: T;
}

Progress is reported against a token. The token is different than the request ID which allows to report progress out of band and also for notification.

Language Server Protocol

The language server protocol defines a set of JSON-RPC request, response and notification messages which are exchanged using the above base protocol. This section starts describing the basic JSON structures used in the protocol. The document uses TypeScript interfaces to describe these. Based on the basic JSON structures, the actual requests with their responses and the notifications are described.

In general, the language server protocol supports JSON-RPC messages, however the base protocol defined here uses a convention such that the parameters passed to request/notification messages should be of object type (if passed at all). However, this does not disallow using Array parameter types in custom messages.

The protocol currently assumes that one server serves one tool. There is currently no support in the protocol to share one server between different tools. Such a sharing would require additional protocol e.g. to lock a document to support concurrent editing.

Basic JSON Structures

URI

URI’s are transferred as strings. The URI’s format is defined in http://tools.ietf.org/html/rfc3986

  foo://example.com:8042/over/there?name=ferret#nose
  \_/   \______________/\_________/ \_________/ \__/
   |           |            |            |        |
scheme     authority       path        query   fragment
   |   _____________________|__
  / \ /                        \
  urn:example:animal:ferret:nose

We also maintain a node module to parse a string into scheme, authority, path, query, and fragment URI components. The GitHub repository is https://github.com/Microsoft/vscode-uri the npm module is https://www.npmjs.com/package/vscode-uri.

Many of the interfaces contain fields that correspond to the URI of a document. For clarity, the type of such a field is declared as a DocumentUri. Over the wire, it will still be transferred as a string, but this guarantees that the contents of that string can be parsed as a valid URI.

type DocumentUri = string;

Text Documents

The current protocol is tailored for textual documents whose content can be represented as a string. There is currently no support for binary documents. A position inside a document (see Position definition below) is expressed as a zero-based line and character offset. The offsets are based on a UTF-16 string representation. So a string of the form a𐐀b the character offset of the character a is 0, the character offset of 𐐀 is 1 and the character offset of b is 3 since 𐐀 is represented using two code units in UTF-16. To ensure that both client and server split the string into the same line representation the protocol specifies the following end-of-line sequences: ‘\n’, ‘\r\n’ and ‘\r’.

Positions are line end character agnostic. So you can not specify a position that denotes \r|\n or \n| where | represents the character offset.

export const EOL: string[] = ['\n', '\r\n', '\r'];

Position

Position in a text document expressed as zero-based line and zero-based character offset. A position is between two characters like an ‘insert’ cursor in a editor. Special values like for example -1 to denote the end of a line are not supported.

interface Position {
	/**
	 * Line position in a document (zero-based).
	 */
	line: number;

	/**
	 * Character offset on a line in a document (zero-based). Assuming that the line is
	 * represented as a string, the `character` value represents the gap between the
	 * `character` and `character + 1`.
	 *
	 * If the character value is greater than the line length it defaults back to the
	 * line length.
	 */
	character: number;
}

Range

A range in a text document expressed as (zero-based) start and end positions. A range is comparable to a selection in an editor. Therefore the end position is exclusive. If you want to specify a range that contains a line including the line ending character(s) then use an end position denoting the start of the next line. For example:

{
    start: { line: 5, character: 23 },
    end : { line 6, character : 0 }
}
interface Range {
	/**
	 * The range's start position.
	 */
	start: Position;

	/**
	 * The range's end position.
	 */
	end: Position;
}

Location

Represents a location inside a resource, such as a line inside a text file.

interface Location {
	uri: DocumentUri;
	range: Range;
}

Represents a link between a source and a target location.

interface LocationLink {

	/**
	 * Span of the origin of this link.
	 *
	 * Used as the underlined span for mouse interaction. Defaults to the word range at
	 * the mouse position.
	 */
	originSelectionRange?: Range;

	/**
	 * The target resource identifier of this link.
	 */
	targetUri: DocumentUri;

	/**
	 * The full target range of this link. If the target for example is a symbol then target range is the
	 * range enclosing this symbol not including leading/trailing whitespace but everything else
	 * like comments. This information is typically used to highlight the range in the editor.
	 */
	targetRange: Range;

	/**
	 * The range that should be selected and revealed when this link is being followed, e.g the name of a function.
	 * Must be contained by the the `targetRange`. See also `DocumentSymbol#range`
	 */
	targetSelectionRange: Range;
}

Diagnostic

Represents a diagnostic, such as a compiler error or warning. Diagnostic objects are only valid in the scope of a resource.

export interface Diagnostic {
	/**
	 * The range at which the message applies.
	 */
	range: Range;

	/**
	 * The diagnostic's severity. Can be omitted. If omitted it is up to the
	 * client to interpret diagnostics as error, warning, info or hint.
	 */
	severity?: DiagnosticSeverity;

	/**
	 * The diagnostic's code, which might appear in the user interface.
	 */
	code?: number | string;

	/**
	 * A human-readable string describing the source of this
	 * diagnostic, e.g. 'typescript' or 'super lint'.
	 */
	source?: string;

	/**
	 * The diagnostic's message.
	 */
	message: string;

	/**
	 * Additional metadata about the diagnostic.
	 *
	 * @since 3.15.0
	 */
	tags?: DiagnosticTag[];

	/**
	 * An array of related diagnostic information, e.g. when symbol-names within
	 * a scope collide all definitions can be marked via this property.
	 */
	relatedInformation?: DiagnosticRelatedInformation[];
}

The protocol currently supports the following diagnostic severities and tags:

export namespace DiagnosticSeverity {
	/**
	 * Reports an error.
	 */
	export const Error = 1;
	/**
	 * Reports a warning.
	 */
	export const Warning = 2;
	/**
	 * Reports an information.
	 */
	export const Information = 3;
	/**
	 * Reports a hint.
	 */
	export const Hint = 4;
}

export type DiagnosticSeverity = 1 | 2 | 3 | 4;

/**
 * The diagnostic tags.
 *
 * @since 3.15.0
 */
export namespace DiagnosticTag {
    /**
     * Unused or unnecessary code.
     *
     * Clients are allowed to render diagnostics with this tag faded out instead of having
     * an error squiggle.
     */
    export const Unnecessary: 1;
    /**
     * Deprecated or obsolete code.
     *
     * Clients are allowed to rendered diagnostics with this tag strike through.
     */
    export const Deprecated: 2;
}

export type DiagnosticTag = 1 | 2;

DiagnosticRelatedInformation is defined as follows:

/**
 * Represents a related message and source code location for a diagnostic. This should be
 * used to point to code locations that cause or related to a diagnostics, e.g when duplicating
 * a symbol in a scope.
 */
export interface DiagnosticRelatedInformation {
	/**
	 * The location of this related diagnostic information.
	 */
	location: Location;

	/**
	 * The message of this related diagnostic information.
	 */
	message: string;
}

Command

Represents a reference to a command. Provides a title which will be used to represent a command in the UI. Commands are identified by a string identifier. The recommended way to handle commands is to implement their execution on the server side if the client and server provides the corresponding capabilities. Alternatively the tool extension code could handle the command. The protocol currently doesn’t specify a set of well-known commands.

interface Command {
	/**
	 * Title of the command, like `save`.
	 */
	title: string;
	/**
	 * The identifier of the actual command handler.
	 */
	command: string;
	/**
	 * Arguments that the command handler should be
	 * invoked with.
	 */
	arguments?: any[];
}

TextEdit

A textual edit applicable to a text document.

interface TextEdit {
	/**
	 * The range of the text document to be manipulated. To insert
	 * text into a document create a range where start === end.
	 */
	range: Range;

	/**
	 * The string to be inserted. For delete operations use an
	 * empty string.
	 */
	newText: string;
}

TextEdit[]

Complex text manipulations are described with an array of TextEdit’s, representing a single change to the document.

All text edits ranges refer to positions in the original document. Text edits ranges must never overlap, that means no part of the original document must be manipulated by more than one edit. However, it is possible that multiple edits have the same start position: multiple inserts, or any number of inserts followed by a single remove or replace edit. If multiple inserts have the same position, the order in the array defines the order in which the inserted strings appear in the resulting text.

TextDocumentEdit

Describes textual changes on a single text document. The text document is referred to as a VersionedTextDocumentIdentifier to allow clients to check the text document version before an edit is applied. A TextDocumentEdit describes all changes on a version Si and after they are applied move the document to version Si+1. So the creator of a TextDocumentEdit doesn’t need to sort the array or do any kind of ordering. However the edits must be non overlapping.

export interface TextDocumentEdit {
	/**
	 * The text document to change.
	 */
	textDocument: VersionedTextDocumentIdentifier;

	/**
	 * The edits to be applied.
	 */
	edits: TextEdit[];
}

File Resource changes

New in version 3.13:

File resource changes allow servers to create, rename and delete files and folders via the client. Note that the names talk about files but the operations are supposed to work on files and folders. This is in line with other naming in the Language Server Protocol (see file watchers which can watch files and folders). The corresponding change literals look as follows:

/**
 * Options to create a file.
 */
export interface CreateFileOptions {
	/**
	 * Overwrite existing file. Overwrite wins over `ignoreIfExists`
	 */
	overwrite?: boolean;
	/**
	 * Ignore if exists.
	 */
	ignoreIfExists?: boolean;
}

/**
 * Create file operation
 */
export interface CreateFile {
	/**
	 * A create
	 */
	kind: 'create';
	/**
	 * The resource to create.
	 */
	uri: DocumentUri;
	/**
	 * Additional options
	 */
	options?: CreateFileOptions;
}

/**
 * Rename file options
 */
export interface RenameFileOptions {
	/**
	 * Overwrite target if existing. Overwrite wins over `ignoreIfExists`
	 */
	overwrite?: boolean;
	/**
	 * Ignores if target exists.
	 */
	ignoreIfExists?: boolean;
}

/**
 * Rename file operation
 */
export interface RenameFile {
	/**
	 * A rename
	 */
	kind: 'rename';
	/**
	 * The old (existing) location.
	 */
	oldUri: DocumentUri;
	/**
	 * The new location.
	 */
	newUri: DocumentUri;
	/**
	 * Rename options.
	 */
	options?: RenameFileOptions;
}

/**
 * Delete file options
 */
export interface DeleteFileOptions {
	/**
	 * Delete the content recursively if a folder is denoted.
	 */
	recursive?: boolean;
	/**
	 * Ignore the operation if the file doesn't exist.
	 */
	ignoreIfNotExists?: boolean;
}

/**
 * Delete file operation
 */
export interface DeleteFile {
	/**
	 * A delete
	 */
	kind: 'delete';
	/**
	 * The file to delete.
	 */
	uri: DocumentUri;
	/**
	 * Delete options.
	 */
	options?: DeleteFileOptions;
}

WorkspaceEdit

A workspace edit represents changes to many resources managed in the workspace. The edit should either provide changes or documentChanges. If the client can handle versioned document edits and if documentChanges are present, the latter are preferred over changes.

export interface WorkspaceEdit {
	/**
	 * Holds changes to existing resources.
	 */
	changes?: { [uri: DocumentUri]: TextEdit[]; };

	/**
	 * Depending on the client capability `workspace.workspaceEdit.resourceOperations` document changes
	 * are either an array of `TextDocumentEdit`s to express changes to n different text documents
	 * where each text document edit addresses a specific version of a text document. Or it can contain
	 * above `TextDocumentEdit`s mixed with create, rename and delete file / folder operations.
	 *
	 * Whether a client supports versioned document edits is expressed via
	 * `workspace.workspaceEdit.documentChanges` client capability.
	 *
	 * If a client neither supports `documentChanges` nor `workspace.workspaceEdit.resourceOperations` then
	 * only plain `TextEdit`s using the `changes` property are supported.
	 */
	documentChanges?: (TextDocumentEdit[] | (TextDocumentEdit | CreateFile | RenameFile | DeleteFile)[]);
}
WorkspaceEditClientCapabilities

New in version 3.13: ResourceOperationKind and FailureHandlingKind and the client capability workspace.workspaceEdit.resourceOperations as well as workspace.workspaceEdit.failureHandling.

The capabilities of a workspace edit has evolved over the time. Clients can describe their support using the following client capability:

  • property path (optional): workspace.workspaceEdit
  • property type: WorkspaceEditClientCapabilities defined as follows:
export interface WorkspaceEditClientCapabilities {
	/**
	 * The client supports versioned document changes in `WorkspaceEdit`s
	 */
	documentChanges?: boolean;

	/**
	 * The resource operations the client supports. Clients should at least
	 * support 'create', 'rename' and 'delete' files and folders.
	 *
	 * @since 3.13.0
	 */
	resourceOperations?: ResourceOperationKind[];

	/**
	 * The failure handling strategy of a client if applying the workspace edit
	 * fails.
	 *
	 * @since 3.13.0
	 */
	failureHandling?: FailureHandlingKind;
}

TextDocumentIdentifier

Text documents are identified using a URI. On the protocol level, URIs are passed as strings. The corresponding JSON structure looks like this:

interface TextDocumentIdentifier {
	/**
	 * The text document's URI.
	 */
	uri: DocumentUri;
}

TextDocumentItem

An item to transfer a text document from the client to the server.

interface TextDocumentItem {
	/**
	 * The text document's URI.
	 */
	uri: DocumentUri;

	/**
	 * The text document's language identifier.
	 */
	languageId: string;

	/**
	 * The version number of this document (it will increase after each
	 * change, including undo/redo).
	 */
	version: number;

	/**
	 * The content of the opened text document.
	 */
	text: string;
}

Text documents have a language identifier to identify a document on the server side when it handles more than one language to avoid re-interpreting the file extension. If a document refers to one of the programming languages listed below it is recommended that clients use those ids.

Language Identifier
ABAP abap
Windows Bat bat
BibTeX bibtex
Clojure clojure
Coffeescript coffeescript
C c
C++ cpp
C# csharp
CSS css
Diff diff
Dart dart
Dockerfile dockerfile
Elixir elixir
Erlang erlang
F# fsharp
Git git-commit and git-rebase
Go go
Groovy groovy
Handlebars handlebars
HTML html
Ini ini
Java java
JavaScript javascript
JavaScript React javascriptreact
JSON json
LaTeX latex
Less less
Lua lua
Makefile makefile
Markdown markdown
Objective-C objective-c
Objective-C++ objective-cpp
Perl perl
Perl 6 perl6
PHP php
Powershell powershell
Pug jade
Python python
R r
Razor (cshtml) razor
Ruby ruby
Rust rust
SCSS scss (syntax using curly brackets), sass (indented syntax)
Scala scala
ShaderLab shaderlab
Shell Script (Bash) shellscript
SQL sql
Swift swift
TypeScript typescript
TypeScript React typescriptreact
TeX tex
Visual Basic vb
XML xml
XSL xsl
YAML yaml

VersionedTextDocumentIdentifier

An identifier to denote a specific version of a text document.

interface VersionedTextDocumentIdentifier extends TextDocumentIdentifier {
	/**
	 * The version number of this document. If a versioned text document identifier
	 * is sent from the server to the client and the file is not open in the editor
	 * (the server has not received an open notification before) the server can send
	 * `null` to indicate that the version is known and the content on disk is the
	 * truth (as speced with document content ownership).
	 *
	 * The version number of a document will increase after each change, including
	 * undo/redo. The number doesn't need to be consecutive.
	 */
	version: number | null;
}

TextDocumentPositionParams

Was TextDocumentPosition in 1.0 with inlined parameters.

A parameter literal used in requests to pass a text document and a position inside that document.

interface TextDocumentPositionParams {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The position inside the text document.
	 */
	position: Position;
}

DocumentFilter

A document filter denotes a document through properties like language, scheme or pattern. An example is a filter that applies to TypeScript files on disk. Another example is a filter the applies to JSON files with name package.json:

{ language: 'typescript', scheme: 'file' }
{ language: 'json', pattern: '**/package.json' }
export interface DocumentFilter {
	/**
	 * A language id, like `typescript`.
	 */
	language?: string;

	/**
	 * A Uri [scheme](#Uri.scheme), like `file` or `untitled`.
	 */
	scheme?: string;

	/**
	 * A glob pattern, like `*.{ts,js}`.
	 *
	 * Glob patterns can have the following syntax:
	 * - `*` to match one or more characters in a path segment
	 * - `?` to match on one character in a path segment
	 * - `**` to match any number of path segments, including none
	 * - `{}` to group conditions (e.g. `**​/*.{ts,js}` matches all TypeScript and JavaScript files)
	 * - `[]` to declare a range of characters to match in a path segment (e.g., `example.[0-9]` to match on `example.0`, `example.1`, …)
	 * - `[!...]` to negate a range of characters to match in a path segment (e.g., `example.[!0-9]` to match on `example.a`, `example.b`, but not `example.0`)
	 */
	pattern?: string;
}

A document selector is the combination of one or more document filters.

export type DocumentSelector = DocumentFilter[];

StaticRegistrationOptions

Static registration options can be used to register a feature in the initialize result with a given server control ID to be able to un-register the feature later on.

/**
 * Static registration options to be returned in the initialize request.
 */
export interface StaticRegistrationOptions {
	/**
	 * The id used to register the request. The id can be used to deregister
	 * the request again. See also Registration#id.
	 */
	id?: string;
}

TextDocumentRegistrationOptions

Options to dynamically register for requests for a set of text documents.

/**
 * General text document registration options.
 */
export interface TextDocumentRegistrationOptions {
	/**
	 * A document selector to identify the scope of the registration. If set to null
	 * the document selector provided on the client side will be used.
	 */
	documentSelector: DocumentSelector | null;
}

MarkupContent

A MarkupContent literal represents a string value which content can be represented in different formats. Currently plaintext and markdown are supported formats. A MarkupContent is usually used in documentation properties of result literals like CompletionItem or SignatureInformation.

/**
 * Describes the content type that a client supports in various
 * result literals like `Hover`, `ParameterInfo` or `CompletionItem`.
 *
 * Please note that `MarkupKinds` must not start with a `$`. This kinds
 * are reserved for internal usage.
 */
export namespace MarkupKind {
	/**
	 * Plain text is supported as a content format
	 */
	export const PlainText: 'plaintext' = 'plaintext';

	/**
	 * Markdown is supported as a content format
	 */
	export const Markdown: 'markdown' = 'markdown';
}
export type MarkupKind = 'plaintext' | 'markdown';

/**
 * A `MarkupContent` literal represents a string value which content is interpreted base on its
 * kind flag. Currently the protocol supports `plaintext` and `markdown` as markup kinds.
 *
 * If the kind is `markdown` then the value can contain fenced code blocks like in GitHub issues.
 * See https://help.github.com/articles/creating-and-highlighting-code-blocks/#syntax-highlighting
 *
 * Here is an example how such a string can be constructed using JavaScript / TypeScript:
 * ```typescript
 * let markdown: MarkdownContent = {
 *  kind: MarkupKind.Markdown,
 *	value: [
 *		'# Header',
 *		'Some text',
 *		'```typescript',
 *		'someCode();',
 *		'```'
 *	].join('\n')
 * };
 * ```
 *
 * *Please Note* that clients might sanitize the return markdown. A client could decide to
 * remove HTML from the markdown to avoid script execution.
 */
export interface MarkupContent {
	/**
	 * The type of the Markup
	 */
	kind: MarkupKind;

	/**
	 * The content itself
	 */
	value: string;
}

Work Done Progress

Since version 3.15.0

Work done progress is reported using the generic $/progress notification. The value payload of a work done progress notification can be of three different forms.

Work Done Progress Begin

To start progress reporting a $/progress notification with the following payload must be sent:

export interface WorkDoneProgressBegin {

	kind: 'begin';

	/**
	 * Mandatory title of the progress operation. Used to briefly inform about
	 * the kind of operation being performed.
	 *
	 * Examples: "Indexing" or "Linking dependencies".
	 */
	title: string;

	/**
	 * Controls if a cancel button should show to allow the user to cancel the
	 * long running operation. Clients that don't support cancellation are allowed
	 * to ignore the setting.
	 */
	cancellable?: boolean;

	/**
	 * Optional, more detailed associated progress message. Contains
	 * complementary information to the `title`.
	 *
	 * Examples: "3/25 files", "project/src/module2", "node_modules/some_dep".
	 * If unset, the previous progress message (if any) is still valid.
	 */
	message?: string;

	/**
	 * Optional progress percentage to display (value 100 is considered 100%).
	 * If not provided infinite progress is assumed and clients are allowed
	 * to ignore the `percentage` value in subsequent in report notifications.
	 *
	 * The value should be steadily rising. Clients are free to ignore values
	 * that are not following this rule.
	 */
	percentage?: number;
}
Work Done Progress Report

Reporting progress is done using the following payload:

export interface WorkDoneProgressReport {

	kind: 'report';

	/**
	 * Controls enablement state of a cancel button. This property is only valid if a cancel
	 * button got requested in the `WorkDoneProgressStart` payload.
	 *
	 * Clients that don't support cancellation or don't support control the button's
	 * enablement state are allowed to ignore the setting.
	 */
	cancellable?: boolean;

	/**
	 * Optional, more detailed associated progress message. Contains
	 * complementary information to the `title`.
	 *
	 * Examples: "3/25 files", "project/src/module2", "node_modules/some_dep".
	 * If unset, the previous progress message (if any) is still valid.
	 */
	message?: string;

	/**
	 * Optional progress percentage to display (value 100 is considered 100%).
	 * If not provided infinite progress is assumed and clients are allowed
	 * to ignore the `percentage` value in subsequent in report notifications.
	 *
	 * The value should be steadily rising. Clients are free to ignore values
	 * that are not following this rule.
	 */
	percentage?: number;
}
Work Done Progress End

Signaling the end of a progress reporting is done using the following payload:

export interface WorkDoneProgressEnd {

	kind: 'end';

	/**
	 * Optional, a final message indicating to for example indicate the outcome
	 * of the operation.
	 */
	message?: string;
}

Initiating Work Done Progress

Work Done progress can be initiated in two different ways:

  1. by the sender of a request (mostly clients) using the predefined workDoneToken property in the requests parameter literal.
  2. by a server using the request window/workDoneProgress/create.

Consider a client sending a textDocument/reference request to a server and the client accepts work done progress reporting on that request. To signal this to the server the client would add a workDoneToken property to the reference request parameters. Something like this:

{
	"textDocument": {
		"uri": "file:///folder/file.ts"
	},
	"position": {
		"line": 9,
		"character": 5
	},
	"context": {
		"includeDeclaration": true
	},
	// The token used to report work done progress.
	"workDoneToken": "1d546990-40a3-4b77-b134-46622995f6ae"
}

A server uses the workDoneToken to report progress for the specific textDocument/reference. For the above request the $/progress notification params look like this:

{
	"token": "1d546990-40a3-4b77-b134-46622995f6ae",
	"value": {
		"title": "Finding references for A#foo",
		"cancellable": false,
		"message": "Processing file X.ts",
		"percentage": 0
	}
}

Server initiated work done progress works the same. The only difference is that the server requests a progress user interface using the window/workDoneProgress/create request providing a token that is afterwards used to report progress.

Signaling Work Done Progress Reporting

To keep the protocol backwards compatible servers are only allowed to use work done progress reporting if the client signals corresponding support using the client capability window.workDoneProgress which is defined as follows:

	/**
	 * Window specific client capabilities.
	 */
	window?: {
		/**
		 * Whether client supports handling progress notifications.
		 */
		workDoneProgress?: boolean;
	}

To avoid that clients set up a progress monitor user interface before sending a request but the server doesn’t actually report any progress a server needs to signal work done progress reporting in the corresponding server capability. For the above find references example a server would signal such a support by setting the referencesProvider property in the server capabilities as follows:

{
	"referencesProvider": {
		"workDoneProgress": true
	}
}

WorkDoneProgressParams

A parameter literal used to pass a work done progress token.

export interface WorkDoneProgressParams {
	/**
	 * An optional token that a server can use to report work done progress.
	 */
	workDoneToken?: ProgressToken;
}

WorkDoneProgressOptions

Options to signal work done progress support in server capabilities.

export interface WorkDoneProgressOptions {
	workDoneProgress?: boolean;
}

Partial Result Progress

Since version 3.15.0

Partial results are also reported using the generic $/progress notification. The value payload of a partial result progress notification is in most cases the same as the final result. For example the workspace/symbol request as SymbolInfomtion[] as the result type. Partial result is therefore also of type SymbolInformation[]. Whether a client accept partial result notifications for a request is signaled by adding a partialResultToken to the request parameters. For example a textDocument/reference request support both work done and partial result progress might look like this:

{
	"textDocument": {
		"uri": "file:///folder/file.ts"
	},
	"position": {
		"line": 9,
		"character": 5
	},
	"context": {
		"includeDeclaration": true
	},
	// The token used to report work done progress.
	"workDoneToken": "1d546990-40a3-4b77-b134-46622995f6ae",
	// The token used to report partial result progress.
	"partialResultToken": "5f6f349e-4f81-4a3b-afff-ee04bff96804"
}

The partialResultToken is then used to report partial results for the find references request.

If a server reports partial result via a corresponding $/progress the whole result must be reported using n $/progress notifications. The final response has to be empty in terms of result values. This avoids confusion about how the final result should be interpreted, e.g. as another partial result or as a replacing result.

PartialResultParams

A parameter literal used to pass a partial result token.

export interface PartialResultParams {
	/**
	 * An optional token that a server can use to report partial results (e.g. streaming) to
	 * the client.
	 */
	partialResultToken?: ProgressToken;
}

Actual Protocol

This section documents the actual language server protocol. It uses the following format:

  • a header describing the request
  • an optional Client capability section describing the client capability of the request. This includes the client capabilities property path and JSON structure.
  • an optional Server Capability section describing the server capability of the request. This includes the server capabilities property path and JSON structure.
  • a Request section describing the format of the request sent. The method is a string identifying the request the params are documented using a TypeScript interface. It is also documented whether the request supports work done progress and partial result progress.
  • a Response section describing the format of the response. The result item describes the returned data in case of a success. The optional partial result item describes the returned data of a partial result notification. The error.data describes the returned data in case of an error. Please remember that in case of a failure the response already contains an error.code and an error.message field. These fields are only spec’d if the protocol forces the use of certain error codes or messages. In cases where the server can decide on these values freely they aren’t listed here.
  • a Registration Options section describing the registration option if the request or notification supports dynamic capability registration.

Request, Notification and Response ordering

Responses to requests should be sent in roughly the same order as the requests appear on the server or client side. So for example if a server receives a textDocument/completion request and then a textDocument/signatureHelp request it will usually first return the response for the textDocument/completion and then the response for textDocument/signatureHelp.

However, the server may decide to use a parallel execution strategy and may wish to return responses in a different order than the requests were received. The server may do so as long as this reordering doesn’t affect the correctness of the responses. For example, reordering the result of textDocument/completion and textDocument/signatureHelp is allowed, as these each of these requests usually won’t affect the output of the other. On the other hand, the server most likely should not reorder textDocument/definition and textDocument/rename requests, since the executing the latter may affect the result of the former.

Server lifetime

The current protocol specification defines that the lifetime of a server is managed by the client (e.g. a tool like VS Code or Emacs). It is up to the client to decide when to start (process-wise) and when to shutdown a server.

Initialize Request (:leftwards_arrow_with_hook:)

The initialize request is sent as the first request from the client to the server. If the server receives a request or notification before the initialize request it should act as follows:

  • For a request the response should be an error with code: -32002. The message can be picked by the server.
  • Notifications should be dropped, except for the exit notification. This will allow the exit of a server without an initialize request.

Until the server has responded to the initialize request with an InitializeResult, the client must not send any additional requests or notifications to the server. In addition the server is not allowed to send any requests or notifications to the client until it has responded with an InitializeResult, with the exception that during the initialize request the server is allowed to send the notifications window/showMessage, window/logMessage and telemetry/event as well as the window/showMessageRequest request to the client.

The initialize request may only be sent once.

Request:

  • method: ‘initialize’
  • params: InitializeParams defined as follows:
interface InitializeParams {
	/**
	 * The process Id of the parent process that started
	 * the server. Is null if the process has not been started by another process.
	 * If the parent process is not alive then the server should exit (see exit notification) its process.
	 */
	processId: number | null;

	/**
	 * Information about the client
	 *
	 * @since 3.15.0
	 */
	clientInfo?: {
		/**
		 * The name of the client as defined by the client.
		 */
		name: string;

		/**
		 * The client's version as defined by the client.
		 */
		version?: string;
	};

	/**
	 * The rootPath of the workspace. Is null
	 * if no folder is open.
	 *
	 * @deprecated in favour of rootUri.
	 */
	rootPath?: string | null;

	/**
	 * The rootUri of the workspace. Is null if no
	 * folder is open. If both `rootPath` and `rootUri` are set
	 * `rootUri` wins.
	 */
	rootUri: DocumentUri | null;

	/**
	 * User provided initialization options.
	 */
	initializationOptions?: any;

	/**
	 * The capabilities provided by the client (editor or tool)
	 */
	capabilities: ClientCapabilities;

	/**
	 * The initial trace setting. If omitted trace is disabled ('off').
	 */
	trace?: 'off' | 'messages' | 'verbose';

	/**
	 * The workspace folders configured in the client when the server starts.
	 * This property is only available if the client supports workspace folders.
	 * It can be `null` if the client supports workspace folders but none are
	 * configured.
	 *
	 * @since 3.6.0
	 */
	workspaceFolders?: WorkspaceFolder[] | null;
}

Where ClientCapabilities and TextDocumentClientCapabilities are defined as follows:

TextDocumentClientCapabilities define capabilities the editor / tool provides on text documents.
/**
 * Text document specific client capabilities.
 */
export interface TextDocumentClientCapabilities {

	synchronization?: TextDocumentSyncClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/completion`
	 */
	completion?: CompletionClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/hover`
	 */
	hover?: HoverClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/signatureHelp`
	 */
	signatureHelp?: SignatureHelpClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/declaration`
	 *
	 * @since 3.14.0
	 */
	declaration?: DeclarationClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/definition`.
	 */
	definition?: DefinitionClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/typeDefinition`
	 *
	 * @since 3.6.0
	 */
	typeDefinition?: TypeDefinitionClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/implementation`.
	 *
	 * @since 3.6.0
	 */
	implementation?: ImplementationClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/references`
	 */
	references?: ReferenceClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/documentHighlight`
	 */
	documentHighlight?: DocumentHighlightClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/documentSymbol`
	 */
	documentSymbol?: DocumentSymbolClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/codeAction`
	 */
	codeAction?: CodeActionClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/codeLens`
	 */
	codeLens?: CodeLensClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/documentLink`
	 */
	documentLink?: DocumentLinkClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/documentColor` and the
	 * `textDocument/colorPresentation` request.
	 *
	 * @since 3.6.0
	 */
	colorProvider?: DocumentColorClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/formatting`
	 */
	formatting?: DocumentFormattingClientCapabilities

	/**
	 * Capabilities specific to the `textDocument/rangeFormatting`
	 */
	rangeFormatting?: DocumentRangeFormattingClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/onTypeFormatting`
	 */
	onTypeFormatting?: DocumentOnTypeFormattingClientCapabilities;

	/**
	 * Capabilities specific to the `textDocument/rename`
	 */
	rename?: RenameClientCapabilities;

	/**
	 * Capabilities specific to `textDocument/publishDiagnostics`.
	 */
	publishDiagnostics?: PublishDiagnosticsClientCapabilities;

	/**
	 * Capabilities specific to `textDocument/foldingRange` requests.
	 *
	 * @since 3.10.0
	 */
	foldingRange?: FoldingRangeClientCapabilities;
}

ClientCapabilities now define capabilities for dynamic registration, workspace and text document features the client supports. The experimental can be used to pass experimental capabilities under development. For future compatibility a ClientCapabilities object literal can have more properties set than currently defined. Servers receiving a ClientCapabilities object literal with unknown properties should ignore these properties. A missing property should be interpreted as an absence of the capability. If a missing property normally defines sub properties, all missing sub properties should be interpreted as an absence of the corresponding capability.

Client capabilities got introduced with version 3.0 of the protocol. They therefore only describe capabilities that got introduced in 3.x or later. Capabilities that existed in the 2.x version of the protocol are still mandatory for clients. Clients cannot opt out of providing them. So even if a client omits the ClientCapabilities.textDocument.synchronization it is still required that the client provides text document synchronization (e.g. open, changed and close notifications).

interface ClientCapabilities {
	/**
	 * Workspace specific client capabilities.
	 */
	workspace?: {
		/**
		* The client supports applying batch edits
		* to the workspace by supporting the request
		* 'workspace/applyEdit'
		*/
		applyEdit?: boolean;

		/**
		* Capabilities specific to `WorkspaceEdit`s
		*/
		workspaceEdit?: WorkspaceEditClientCapabilities;

		/**
		* Capabilities specific to the `workspace/didChangeConfiguration` notification.
		*/
		didChangeConfiguration?: DidChangeConfigurationClientCapabilities;

		/**
		* Capabilities specific to the `workspace/didChangeWatchedFiles` notification.
		*/
		didChangeWatchedFiles?: DidChangeWatchedFilesClientCapabilities;

		/**
		* Capabilities specific to the `workspace/symbol` request.
		*/
		symbol?: WorkspaceSymbolClientCapabilities;

		/**
		* Capabilities specific to the `workspace/executeCommand` request.
		*/
		executeCommand?: ExecuteCommandClientCapabilities;
	};

	/**
	 * Text document specific client capabilities.
	 */
	textDocument?: TextDocumentClientCapabilities;

	/**
	 * Experimental client capabilities.
	 */
	experimental?: any;
}

Response:

  • result: InitializeResult defined as follows:
interface InitializeResult {
	/**
	 * The capabilities the language server provides.
	 */
	capabilities: ServerCapabilities;

	/**
	 * Information about the server.
	 *
	 * @since 3.15.0
	 */
	serverInfo?: {
		/**
		 * The name of the server as defined by the server.
		 */
		name: string;

		/**
		 * The servers's version as defined by the server.
		 */
		version?: string;
	};
}
  • error.code:
/**
 * Known error codes for an `InitializeError`;
 */
export namespace InitializeError {
	/**
	 * If the protocol version provided by the client can't be handled by the server.
	 * @deprecated This initialize error got replaced by client capabilities. There is
	 * no version handshake in version 3.0x
	 */
	export const unknownProtocolVersion: number = 1;
}
  • error.data:
interface InitializeError {
	/**
	 * Indicates whether the client execute the following retry logic:
	 * (1) show the message provided by the ResponseError to the user
	 * (2) user selects retry or cancel
	 * (3) if user selected retry the initialize method is sent again.
	 */
	retry: boolean;
}

The server can signal the following capabilities:

/**
 * Execute command options.
 */
export interface ExecuteCommandOptions {
	/**
	 * The commands to be executed on the server
	 */
	commands: string[]
}

interface ServerCapabilities {
	/**
	 * Defines how text documents are synced. Is either a detailed structure defining each notification or
	 * for backwards compatibility the TextDocumentSyncKind number. If omitted it defaults to `TextDocumentSyncKind.None`.
	 */
	textDocumentSync?: TextDocumentSyncOptions | number;

	/**
	 * The server provides completion support.
	 */
	completionProvider?: CompletionOptions;

	/**
	 * The server provides hover support.
	 */
	hoverProvider?: boolean | HoverOptions;

	/**
	 * The server provides signature help support.
	 */
	signatureHelpProvider?: SignatureHelpOptions;

	/**
	 * The server provides go to declaration support.
	 *
	 * @since 3.14.0
	 */
	declarationProvider?: boolean | DeclarationOptions | DeclarationRegistrationOptions;

	/**
	 * The server provides goto definition support.
	 */
	definitionProvider?: boolean | DefinitionOptions;

	/**
	 * The server provides Goto Type Definition support.
	 *
	 * @since 3.6.0
	 */
	typeDefinitionProvider?: boolean | TypeDefinitionOptions | TypeDefinitionRegistrationOptions;

	/**
	 * The server provides Goto Implementation support.
	 *
	 * @since 3.6.0
	 */
	implementationProvider?: boolean | ImplementationOptions | ImplementationRegistrationOptions;

	/**
	 * The server provides find references support.
	 */
	referencesProvider?: boolean | ReferenceOptions;

	/**
	 * The server provides document highlight support.
	 */
	documentHighlightProvider?: boolean | DocumentHighlightOptions;

	/**
	 * The server provides document symbol support.
	 */
	documentSymbolProvider?: boolean | DocumentSymbolOptions;

	/**
	 * The server provides code actions. The `CodeActionOptions` return type is only
	 * valid if the client signals code action literal support via the property
	 * `textDocument.codeAction.codeActionLiteralSupport`.
	 */
	codeActionProvider?: boolean | CodeActionOptions;

	/**
	 * The server provides code lens.
	 */
	codeLensProvider?: CodeLensOptions;

	/**
	 * The server provides document link support.
	 */
	documentLinkProvider?: DocumentLinkOptions;

	/**
	 * The server provides color provider support.
	 *
	 * @since 3.6.0
	 */
	colorProvider?: boolean | DocumentColorOptions | DocumentColorRegistrationOptions;

	/**
	 * The server provides document formatting.
	 */
	documentFormattingProvider?: boolean | DocumentFormattingOptions;

	/**
	 * The server provides document range formatting.
	 */
	documentRangeFormattingProvider?: boolean | DocumentRangeFormattingOptions;

	/**
	 * The server provides document formatting on typing.
	 */
	documentOnTypeFormattingProvider?: DocumentOnTypeFormattingOptions;

	/**
	 * The server provides rename support. RenameOptions may only be
	 * specified if the client states that it supports
	 * `prepareSupport` in its initial `initialize` request.
	 */
	renameProvider?: boolean | RenameOptions;

	/**
	 * The server provides folding provider support.
	 *
	 * @since 3.10.0
	 */
	foldingRangeProvider?: boolean | FoldingRangeOptions | FoldingRangeRegistrationOptions;

	/**
	 * The server provides folding provider support.
	 *
	 * @since 3.10.0
	 */
	foldingRangeProvider?: boolean | FoldingRangeOptions | FoldingRangeRegistrationOptions;

	/**
	 * The server provides execute command support.
	 */
	executeCommandProvider?: ExecuteCommandOptions;

	/**
	 * The server provides workspace symbol support.
	 */
	workspaceSymbolProvider?: boolean;

	/**
	 * Workspace specific server capabilities
	 */
	workspace?: {
		/**
		 * The server supports workspace folder.
		 *
		 * @since 3.6.0
		 */
		workspaceFolders?: WorkspaceFoldersServerCapabilities;
	}

	/**
	 * Experimental server capabilities.
	 */
	experimental?: any;
}

Initialized Notification (:arrow_right:)

The initialized notification is sent from the client to the server after the client received the result of the initialize request but before the client is sending any other request or notification to the server. The server can use the initialized notification for example to dynamically register capabilities. The initialized notification may only be sent once.

Notification:

  • method: ‘initialized’
  • params: InitializedParams defined as follows:
interface InitializedParams {
}

Shutdown Request (:leftwards_arrow_with_hook:)

The shutdown request is sent from the client to the server. It asks the server to shut down, but to not exit (otherwise the response might not be delivered correctly to the client). There is a separate exit notification that asks the server to exit. Clients must not send any notifications other than exit or requests to a server to which they have sent a shutdown request. If a server receives requests after a shutdown request those requests should error with InvalidRequest.

Request:

  • method: ‘shutdown’
  • params: void

Response:

  • result: null
  • error: code and message set in case an exception happens during shutdown request.

Exit Notification (:arrow_right:)

A notification to ask the server to exit its process. The server should exit with success code 0 if the shutdown request has been received before; otherwise with error code 1.

Notification:

  • method: ‘exit’
  • params: void

ShowMessage Notification (:arrow_left:)

The show message notification is sent from a server to a client to ask the client to display a particular message in the user interface.

Notification:

  • method: ‘window/showMessage’
  • params: ShowMessageParams defined as follows:
interface ShowMessageParams {
	/**
	 * The message type. See {@link MessageType}.
	 */
	type: number;

	/**
	 * The actual message.
	 */
	message: string;
}

Where the type is defined as follows:

export namespace MessageType {
	/**
	 * An error message.
	 */
	export const Error = 1;
	/**
	 * A warning message.
	 */
	export const Warning = 2;
	/**
	 * An information message.
	 */
	export const Info = 3;
	/**
	 * A log message.
	 */
	export const Log = 4;
}

ShowMessage Request (:arrow_right_hook:)

The show message request is sent from a server to a client to ask the client to display a particular message in the user interface. In addition to the show message notification the request allows to pass actions and to wait for an answer from the client.

Request:

  • method: ‘window/showMessageRequest’
  • params: ShowMessageRequestParams defined as follows:

Response:

  • result: the selected MessageActionItem | null if none got selected.
  • error: code and message set in case an exception happens during showing a message.
interface ShowMessageRequestParams {
	/**
	 * The message type. See {@link MessageType}
	 */
	type: number;

	/**
	 * The actual message
	 */
	message: string;

	/**
	 * The message action items to present.
	 */
	actions?: MessageActionItem[];
}

Where the MessageActionItem is defined as follows:

interface MessageActionItem {
	/**
	 * A short title like 'Retry', 'Open Log' etc.
	 */
	title: string;
}

LogMessage Notification (:arrow_left:)

The log message notification is sent from the server to the client to ask the client to log a particular message.

Notification:

  • method: ‘window/logMessage’
  • params: LogMessageParams defined as follows:
interface LogMessageParams {
	/**
	 * The message type. See {@link MessageType}
	 */
	type: number;

	/**
	 * The actual message
	 */
	message: string;
}

Where type is defined as above.

Telemetry Notification (:arrow_left:)

The telemetry notification is sent from the server to the client to ask the client to log a telemetry event.

Notification:

  • method: ‘telemetry/event’
  • params: ‘any’

Register Capability (:arrow_right_hook:)

The client/registerCapability request is sent from the server to the client to register for a new capability on the client side. Not all clients need to support dynamic capability registration. A client opts in via the dynamicRegistration property on the specific client capabilities. A client can even provide dynamic registration for capability A but not for capability B (see TextDocumentClientCapabilities as an example).

Server must not register the same capability both statically through the initialize result and dynamically for the same document selector. If a server wants to support both static and dynamic registration it needs to check the client capability in the initialize request and only register the capability statically if the client doesn’t support dynamic registration for that capability.

Request:

  • method: ‘client/registerCapability’
  • params: RegistrationParams

Where RegistrationParams are defined as follows:

/**
 * General parameters to register for a capability.
 */
export interface Registration {
	/**
	 * The id used to register the request. The id can be used to deregister
	 * the request again.
	 */
	id: string;

	/**
	 * The method / capability to register for.
	 */
	method: string;

	/**
	 * Options necessary for the registration.
	 */
	registerOptions?: any;
}

export interface RegistrationParams {
	registrations: Registration[];
}

Since most of the registration options require to specify a document selector there is a base interface that can be used.

export interface TextDocumentRegistrationOptions {
	/**
	 * A document selector to identify the scope of the registration. If set to null
	 * the document selector provided on the client side will be used.
	 */
	documentSelector: DocumentSelector | null;
}

An example JSON RPC message to register dynamically for the textDocument/willSaveWaitUntil feature on the client side is as follows (only details shown):

{
	"method": "client/registerCapability",
	"params": {
		"registrations": [
			{
				"id": "79eee87c-c409-4664-8102-e03263673f6f",
				"method": "textDocument/willSaveWaitUntil",
				"registerOptions": {
					"documentSelector": [
						{ "language": "javascript" }
					]
				}
			}
		]
	}
}

This message is sent from the server to the client and after the client has successfully executed the request further textDocument/willSaveWaitUntil requests for JavaScript text documents are sent from the client to the server.

Response:

  • result: void.
  • error: code and message set in case an exception happens during the request.

Unregister Capability (:arrow_right_hook:)

The client/unregisterCapability request is sent from the server to the client to unregister a previously registered capability.

Request:

  • method: ‘client/unregisterCapability’
  • params: UnregistrationParams

Where UnregistrationParams are defined as follows:

/**
 * General parameters to unregister a capability.
 */
export interface Unregistration {
	/**
	 * The id used to unregister the request or notification. Usually an id
	 * provided during the register request.
	 */
	id: string;

	/**
	 * The method / capability to unregister for.
	 */
	method: string;
}

export interface UnregistrationParams {
	// This should correctly be named `unregistrations`. However changing this
	// is a breaking change and needs to wait until we deliver a 4.x version
	// of the specification.
	unregisterations: Unregistration[];
}

An example JSON RPC message to unregister the above registered textDocument/willSaveWaitUntil feature looks like this:

{
	"method": "client/unregisterCapability",
	"params": {
		"unregisterations": [
			{
				"id": "79eee87c-c409-4664-8102-e03263673f6f",
				"method": "textDocument/willSaveWaitUntil"
			}
		]
	}
}

Response:

  • result: void.
  • error: code and message set in case an exception happens during the request.
Workspace folders request (:arrow_right_hook:)

Since version 3.6.0

Many tools support more than one root folder per workspace. Examples for this are VS Code’s multi-root support, Atom’s project folder support or Sublime’s project support. If a client workspace consists of multiple roots then a server typically needs to know about this. The protocol up to now assumes one root folder which is announced to the server by the rootUri property of the InitializeParams. If the client supports workspace folders and announces them via the corresponding workspaceFolders client capability, the InitializeParams contain an additional property workspaceFolders with the configured workspace folders when the server starts.

The workspace/workspaceFolders request is sent from the server to the client to fetch the current open list of workspace folders. Returns null in the response if only a single file is open in the tool. Returns an empty array if a workspace is open but no folders are configured.

Client Capability:

  • property path (optional): workspace.workspaceFolders
  • property type: boolean

Server Capability:

  • property path (optional): workspace.workspaceFolders
  • property type: WorkspaceFoldersServerCapabilities defined as follows:
export interface WorkspaceFoldersServerCapabilities {
	/**
	 * The Server has support for workspace folders
	 */
	supported?: boolean;

	/**
	 * Whether the server wants to receive workspace folder
	 * change notifications.
	 *
	 * If a strings is provided the string is treated as a ID
	 * under which the notification is registed on the client
	 * side. The ID can be used to unregister for these events
	 * using the `client/unregisterCapability` request.
	 */
	changeNotifications?: string | boolean;
}

Request:

  • method: ‘workspace/workspaceFolders’
  • params: none

Response:

  • result: WorkspaceFolder[] | null defined as follows:
export interface WorkspaceFolder {
	/**
	 * The associated URI for this workspace folder.
	 */
	uri: DocumentUri;

	/**
	 * The name of the workspace folder. Used to refer to this
	 * workspace folder in the user interface.
	 */
	name: string;
}
  • error: code and message set in case an exception happens during the ‘workspace/workspaceFolders’ request
DidChangeWorkspaceFolders Notification (:arrow_right:)

Since version 3.6.0

The workspace/didChangeWorkspaceFolders notification is sent from the client to the server to inform the server about workspace folder configuration changes. The notification is sent by default if both client capability workspace.workspaceFolders and the server capability workspace.workspaceFolders.supported are true; or if the server has registered itself to receive this notification. To register for the workspace/didChangeWorkspaceFolders send a client/registerCapability request from the server to the client. The registration parameter must have a registrations item of the following form, where id is a unique id used to unregister the capability (the example uses a UUID):

{
	id: "28c6150c-bd7b-11e7-abc4-cec278b6b50a",
	method: "workspace/didChangeWorkspaceFolders"
}

Notification:

  • method: ‘workspace/didChangeWorkspaceFolders’
  • params: DidChangeWorkspaceFoldersParams defined as follows:
export interface DidChangeWorkspaceFoldersParams {
	/**
	 * The actual workspace folder change event.
	 */
	event: WorkspaceFoldersChangeEvent;
}

/**
 * The workspace folder change event.
 */
export interface WorkspaceFoldersChangeEvent {
	/**
	 * The array of added workspace folders
	 */
	added: WorkspaceFolder[];

	/**
	 * The array of the removed workspace folders
	 */
	removed: WorkspaceFolder[];
}

DidChangeConfiguration Notification (:arrow_right:)

A notification sent from the client to the server to signal the change of configuration settings.

Client Capability:

  • property path (optional): workspace.didChangeConfiguration
  • property type: DidChangeConfigurationClientCapabilities defined as follows:
export interface DidChangeConfigurationClientCapabilities {
	/**
	 * Did change configuration notification supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Notification:

  • method: ‘workspace/didChangeConfiguration’,
  • params: DidChangeConfigurationParams defined as follows:
interface DidChangeConfigurationParams {
	/**
	 * The actual changed settings
	 */
	settings: any;
}

Configuration Request (:arrow_right_hook:)

Since version 3.6.0

The workspace/configuration request is sent from the server to the client to fetch configuration settings from the client. The request can fetch several configuration settings in one roundtrip. The order of the returned configuration settings correspond to the order of the passed ConfigurationItems (e.g. the first item in the response is the result for the first configuration item in the params).

A ConfigurationItem consists of the configuration section to ask for and an additional scope URI. The configuration section ask for is defined by the server and doesn’t necessarily need to correspond to the configuration store used be the client. So a server might ask for a configuration cpp.formatterOptions but the client stores the configuration in a XML store layout differently. It is up to the client to do the necessary conversion. If a scope URI is provided the client should return the setting scoped to the provided resource. If the client for example uses EditorConfig to manage its settings the configuration should be returned for the passed resource URI. If the client can’t provide a configuration setting for a given scope then null need to be present in the returned array.

Client Capability:

  • property path (optional): workspace.configuration
  • property type: boolean

Request:

  • method: ‘workspace/configuration’
  • params: ConfigurationParams defined as follows
export interface ConfigurationParams {
	items: ConfigurationItem[];
}

export interface ConfigurationItem {
	/**
	 * The scope to get the configuration section for.
	 */
	scopeUri?: DocumentUri;

	/**
	 * The configuration section asked for.
	 */
	section?: string;
}

Response:

  • result: any[]
  • error: code and message set in case an exception happens during the ‘workspace/configuration’ request

DidChangeWatchedFiles Notification (:arrow_right:)

The watched files notification is sent from the client to the server when the client detects changes to files watched by the language client. It is recommended that servers register for these file events using the registration mechanism. In former implementations clients pushed file events without the server actively asking for it.

Servers are allowed to run their own file watching mechanism and not rely on clients to provide file events. However this is not recommended due to the following reasons:

  • to our experience getting file watching on disk right is challenging, especially if it needs to be supported across multiple OSes.
  • file watching is not for free especially if the implementation uses some sort of polling and keeps a file tree in memory to compare time stamps (as for example some node modules do)
  • a client usually starts more than one server. If every server runs its own file watching it can become a CPU or memory problem.
  • in general there are more server than client implementations. So this problem is better solved on the client side.

Client Capability:

  • property path (optional): workspace.didChangeWatchedFiles
  • property type: DidChangeWatchedFilesClientCapabilities defined as follows:
export interface DidChangeWatchedFilesClientCapabilities {
	/**
	 * Did change watched files notification supports dynamic registration. Please note
	 * that the current protocol doesn't support static configuration for file changes
	 * from the server side.
	 */
	dynamicRegistration?: boolean;
}

Registration Options: DidChangeWatchedFilesRegistrationOptions defined as follows:

/**
 * Describe options to be used when registering for file system change events.
 */
export interface DidChangeWatchedFilesRegistrationOptions {
	/**
	 * The watchers to register.
	 */
	watchers: FileSystemWatcher[];
}

export interface FileSystemWatcher {
	/**
	 * The  glob pattern to watch.
	 *
	 * Glob patterns can have the following syntax:
	 * - `*` to match one or more characters in a path segment
	 * - `?` to match on one character in a path segment
	 * - `**` to match any number of path segments, including none
	 * - `{}` to group conditions (e.g. `**​/*.{ts,js}` matches all TypeScript and JavaScript files)
	 * - `[]` to declare a range of characters to match in a path segment (e.g., `example.[0-9]` to match on `example.0`, `example.1`, …)
	 * - `[!...]` to negate a range of characters to match in a path segment (e.g., `example.[!0-9]` to match on `example.a`, `example.b`, but not `example.0`)
	 */
	globPattern: string;

	/**
	 * The kind of events of interest. If omitted it defaults
	 * to WatchKind.Create | WatchKind.Change | WatchKind.Delete
	 * which is 7.
	 */
	kind?: number;
}

export namespace WatchKind {
	/**
	 * Interested in create events.
	 */
	export const Create = 1;

	/**
	 * Interested in change events
	 */
	export const Change = 2;

	/**
	 * Interested in delete events
	 */
	export const Delete = 4;
}

Notification:

  • method: ‘workspace/didChangeWatchedFiles’
  • params: DidChangeWatchedFilesParams defined as follows:
interface DidChangeWatchedFilesParams {
	/**
	 * The actual file events.
	 */
	changes: FileEvent[];
}

Where FileEvents are described as follows:

/**
 * An event describing a file change.
 */
interface FileEvent {
	/**
	 * The file's URI.
	 */
	uri: DocumentUri;
	/**
	 * The change type.
	 */
	type: number;
}

/**
 * The file event type.
 */
export namespace FileChangeType {
	/**
	 * The file got created.
	 */
	export const Created = 1;
	/**
	 * The file got changed.
	 */
	export const Changed = 2;
	/**
	 * The file got deleted.
	 */
	export const Deleted = 3;
}

Workspace Symbols Request (:leftwards_arrow_with_hook:)

The workspace symbol request is sent from the client to the server to list project-wide symbols matching the query string.

Client Capability:

  • property path (optional): workspace.symbol
  • property type: WorkspaceSymbolClientCapabilities defined as follows:
interface WorkspaceSymbolClientCapabilities {
	/**
	 * Symbol request supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * Specific capabilities for the `SymbolKind` in the `workspace/symbol` request.
	 */
	symbolKind?: {
		/**
		 * The symbol kind values the client supports. When this
		 * property exists the client also guarantees that it will
		 * handle values outside its set gracefully and falls back
		 * to a default value when unknown.
		 *
		 * If this property is not present the client only supports
		 * the symbol kinds from `File` to `Array` as defined in
		 * the initial version of the protocol.
		 */
		valueSet?: SymbolKind[];
	}
}

Server Capability:

  • property path (optional): workspaceSymbolProvider
  • property type: boolean | WorkspaceSymbolOptions were WorkspaceSymbolOptions is defined as follows:
export interface WorkspaceSymbolOptions extends WorkDoneProgressOptions {
}

Registration Options: WorkspaceSymbolRegistrationOptions defined as follows:

export interface WorkspaceSymbolRegistrationOptions extends WorkspaceSymbolOptions {
}

Request:

  • method: ‘workspace/symbol’
  • params: WorkspaceSymbolParams defined as follows:
/**
 * The parameters of a Workspace Symbol Request.
 */
interface WorkspaceSymbolParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * A query string to filter symbols by. Clients may send an empty
	 * string here to request all symbols.
	 */
	query: string;
}

Response:

  • result: SymbolInformation[] | null as defined above.
  • partial result: SymbolInformation[] as defined above.
  • error: code and message set in case an exception happens during the workspace symbol request.

Execute a command (:leftwards_arrow_with_hook:)

The workspace/executeCommand request is sent from the client to the server to trigger command execution on the server. In most cases the server creates a WorkspaceEdit structure and applies the changes to the workspace using the request workspace/applyEdit which is sent from the server to the client.

Client Capability:

  • property path (optional): workspace.executeCommand
  • property type: ExecuteCommandClientCapabilities defined as follows:
export interface ExecuteCommandClientCapabilities {
	/**
	 * Execute command supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property path (optional): executeCommandProvider
  • property type: ExecuteCommandOptions defined as follows:
export interface ExecuteCommandOptions extends WorkDoneProgressOptions {
	/**
	 * The commands to be executed on the server
	 */
	commands: string[]
}

Registration Options: ExecuteCommandRegistrationOptions defined as follows:

/**
 * Execute command registration options.
 */
export interface ExecuteCommandRegistrationOptions extends ExecuteCommandOptions {
}

Request:

  • method: ‘workspace/executeCommand’
  • params: ExecuteCommandParams defined as follows:
export interface ExecuteCommandParams extends WorkDoneProgressParams {

	/**
	 * The identifier of the actual command handler.
	 */
	command: string;
	/**
	 * Arguments that the command should be invoked with.
	 */
	arguments?: any[];
}

The arguments are typically specified when a command is returned from the server to the client. Example requests that return a command are textDocument/codeAction or textDocument/codeLens.

Response:

  • result: any | null
  • error: code and message set in case an exception happens during the request.

Applies a WorkspaceEdit (:arrow_right_hook:)

The workspace/applyEdit request is sent from the server to the client to modify resource on the client side.

Client Capability:

  • property path (optional): workspace.applyEdit
  • property type: boolean

See also the WorkspaceEditClientCapabilities for the supported capabilities of a workspace edit.

Request:

  • method: ‘workspace/applyEdit’
  • params: ApplyWorkspaceEditParams defined as follows:
export interface ApplyWorkspaceEditParams {
	/**
	 * An optional label of the workspace edit. This label is
	 * presented in the user interface for example on an undo
	 * stack to undo the workspace edit.
	 */
	label?: string;

	/**
	 * The edits to apply.
	 */
	edit: WorkspaceEdit;
}

Response:

  • result: ApplyWorkspaceEditResponse defined as follows:
export interface ApplyWorkspaceEditResponse {
	/**
	 * Indicates whether the edit was applied or not.
	 */
	applied: boolean;

	/**
	 * An optional textual description for why the edit was not applied.
	 * This may be used may be used by the server for diagnostic
	 * logging or to provide a suitable error for a request that
	 * triggered the edit.
	 */
	failureReason?: string;
}
  • error: code and message set in case an exception happens during the request.

Text Document Synchronization

Client support for textDocument/open, textDocument/change and textDocument/close notifications is mandantory in the protocol and clients can not opt out supporting them. In addition a server must either implement all three of them or none. Their capabilities are therefore controlled via a combined client and server capability.

Client Capability:

  • property path (optional): textDocument.synchronization.dynamicRegistration
  • property type: boolean

Controls whether text document synchronization supports dynamic registration.

Server Capability:

  • property path (optional): textDocumentSync
  • property type: TextDocumentSyncKind | TextDocumentSyncOptions both defined as follows:
/**
 * Defines how the host (editor) should sync document changes to the language server.
 */
export namespace TextDocumentSyncKind {
	/**
	 * Documents should not be synced at all.
	 */
	export const None = 0;

	/**
	 * Documents are synced by always sending the full content
	 * of the document.
	 */
	export const Full = 1;

	/**
	 * Documents are synced by sending the full content on open.
	 * After that only incremental updates to the document are
	 * send.
	 */
	export const Incremental = 2;
}

export interface TextDocumentSyncOptions {
	/**
	 * Open and close notifications are sent to the server. If omitted open close notification should not
	 * be sent.
	 */
	openClose?: boolean;
	/**
	 * Change notifications are sent to the server. See TextDocumentSyncKind.None, TextDocumentSyncKind.Full
	 * and TextDocumentSyncKind.Incremental. If omitted it defaults to TextDocumentSyncKind.None.
	 */
	change?: TextDocumentSyncKind;
}

DidOpenTextDocument Notification (:arrow_right:)

The document open notification is sent from the client to the server to signal newly opened text documents. The document’s truth is now managed by the client and the server must not try to read the document’s truth using the document’s Uri. Open in this sense means it is managed by the client. It doesn’t necessarily mean that its content is presented in an editor. An open notification must not be sent more than once without a corresponding close notification send before. This means open and close notification must be balanced and the max open count for a particular textDocument is one. Note that a server’s ability to fulfill requests is independent of whether a text document is open or closed.

The DidOpenTextDocumentParams contain the language id the document is associated with. If the language Id of a document changes, the client needs to send a textDocument/didClose to the server followed by a textDocument/didOpen with the new language id if the server handles the new language id as well.

Client Capability: See general synchronization client capabilities.

Server Capability: See general synchronization server capabilities.

Registration Options: TextDocumentRegistrationOptions

Notification:

  • method: ‘textDocument/didOpen’
  • params: DidOpenTextDocumentParams defined as follows:
interface DidOpenTextDocumentParams {
	/**
	 * The document that was opened.
	 */
	textDocument: TextDocumentItem;
}

DidChangeTextDocument Notification (:arrow_right:)

The document change notification is sent from the client to the server to signal changes to a text document. Before a client can change a text document it must claim ownership of its content using the textDocument/didOpen notification. In 2.0 the shape of the params has changed to include proper version numbers and language ids.

Client Capability: See general synchronization client capabilities.

Server Capability: See general synchronization server capabilities.

Registration Options: TextDocumentChangeRegistrationOptions defined as follows:

/**
 * Describe options to be used when registering for text document change events.
 */
export interface TextDocumentChangeRegistrationOptions extends TextDocumentRegistrationOptions {
	/**
	 * How documents are synced to the server. See TextDocumentSyncKind.Full
	 * and TextDocumentSyncKind.Incremental.
	 */
	syncKind: number;
}

Notification:

  • method: ‘textDocument/didChange’
  • params: DidChangeTextDocumentParams defined as follows:
interface DidChangeTextDocumentParams {
	/**
	 * The document that did change. The version number points
	 * to the version after all provided content changes have
	 * been applied.
	 */
	textDocument: VersionedTextDocumentIdentifier;

	/**
	 * The actual content changes. The content changes describe single state changes
	 * to the document. So if there are two content changes c1 and c2 for a document
	 * in state S then c1 move the document to S' and c2 to S''.
	 */
	contentChanges: TextDocumentContentChangeEvent[];
}

/**
 * An event describing a change to a text document. If range and rangeLength are omitted
 * the new text is considered to be the full content of the document.
 */
interface TextDocumentContentChangeEvent {
	/**
	 * The range of the document that changed.
	 */
	range?: Range;

	/**
	 * The length of the range that got replaced.
	 */
	rangeLength?: number;

	/**
	 * The new text of the range/document.
	 */
	text: string;
}

WillSaveTextDocument Notification (:arrow_right:)

The document will save notification is sent from the client to the server before the document is actually saved.

Client Capability:

  • property name (optional): textDocument.synchronization.willSave
  • property type: boolean

The capability indicates that the client supports textDocument/willSave notifications.

Server Capability:

  • property name (optional): textDocumentSync.willSave
  • property type: boolean

The capability indicates that the server is interested in textDocument/willSave notifications.

Registration Options: TextDocumentRegistrationOptions

Notification:

  • method: ‘textDocument/willSave’
  • params: WillSaveTextDocumentParams defined as follows:
/**
 * The parameters send in a will save text document notification.
 */
export interface WillSaveTextDocumentParams {
	/**
	 * The document that will be saved.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The 'TextDocumentSaveReason'.
	 */
	reason: number;
}

/**
 * Represents reasons why a text document is saved.
 */
export namespace TextDocumentSaveReason {

	/**
	 * Manually triggered, e.g. by the user pressing save, by starting debugging,
	 * or by an API call.
	 */
	export const Manual = 1;

	/**
	 * Automatic after a delay.
	 */
	export const AfterDelay = 2;

	/**
	 * When the editor lost focus.
	 */
	export const FocusOut = 3;
}

WillSaveWaitUntilTextDocument Request (:leftwards_arrow_with_hook:)

The document will save request is sent from the client to the server before the document is actually saved. The request can return an array of TextEdits which will be applied to the text document before it is saved. Please note that clients might drop results if computing the text edits took too long or if a server constantly fails on this request. This is done to keep the save fast and reliable.

Client Capability:

  • property name (optional): textDocument.synchronization.willSaveWaitUntil
  • property type: boolean

The capability indicates that the client supports textDocument/willSaveWaitUntil requests.

Server Capability:

  • property name (optional): textDocumentSync.willSaveWaitUntil
  • property type: boolean

The capability indicates that the server is interested in textDocument/willSaveWaitUntil requests.

Registration Options: TextDocumentRegistrationOptions

Request:

  • method: ‘textDocument/willSaveWaitUntil’
  • params: WillSaveTextDocumentParams

Response:

  • result:TextEdit[] | null
  • error: code and message set in case an exception happens during the willSaveWaitUntil request.

DidSaveTextDocument Notification (:arrow_right:)

The document save notification is sent from the client to the server when the document was saved in the client.

Client Capability:

  • property name (optional): textDocument.synchronization.didSave
  • property type: boolean

The capability indicates that the client supports textDocument/didSave notifications.

Server Capability:

  • property name (optional): textDocumentSync.didSave
  • property type: boolean | SaveOptions were SaveOptions is defined as follows:
export interface SaveOptions {
	/**
	 * The client is supposed to include the content on save.
	 */
	includeText?: boolean;
}

The capability indicates that the server is interested in textDocument/didSave notifications.

Registration Options: TextDocumentSaveRegistrationOptions defined as follows:

export interface TextDocumentSaveRegistrationOptions extends TextDocumentRegistrationOptions {
	/**
	 * The client is supposed to include the content on save.
	 */
	includeText?: boolean;
}

Notification:

  • method: ‘textDocument/didSave’
  • params: DidSaveTextDocumentParams defined as follows:
interface DidSaveTextDocumentParams {
	/**
	 * The document that was saved.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * Optional the content when saved. Depends on the includeText value
	 * when the save notification was requested.
	 */
	text?: string;
}

DidCloseTextDocument Notification (:arrow_right:)

The document close notification is sent from the client to the server when the document got closed in the client. The document’s truth now exists where the document’s Uri points to (e.g. if the document’s Uri is a file Uri the truth now exists on disk). As with the open notification the close notification is about managing the document’s content. Receiving a close notification doesn’t mean that the document was open in an editor before. A close notification requires a previous open notification to be sent. Note that a server’s ability to fulfill requests is independent of whether a text document is open or closed.

Client Capability: See general synchronization client capabilities.

Server Capability: See general synchronization server capabilities.

Registration Options: TextDocumentRegistrationOptions

Notification:

  • method: ‘textDocument/didClose’
  • params: DidCloseTextDocumentParams defined as follows:
interface DidCloseTextDocumentParams {
	/**
	 * The document that was closed.
	 */
	textDocument: TextDocumentIdentifier;
}

The final structure of the TextDocumentSyncClientCapabilities and the TextDocumentSyncOptions server options look like this

export interface TextDocumentSyncClientCapabilities {
	/**
	 * Whether text document synchronization supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports sending will save notifications.
	 */
	willSave?: boolean;

	/**
	 * The client supports sending a will save request and
	 * waits for a response providing text edits which will
	 * be applied to the document before it is saved.
	 */
	willSaveWaitUntil?: boolean;

	/**
	 * The client supports did save notifications.
	 */
	didSave?: boolean;
}

/**
 * Defines how the host (editor) should sync document changes to the language server.
 */
export namespace TextDocumentSyncKind {
	/**
	 * Documents should not be synced at all.
	 */
	export const None = 0;

	/**
	 * Documents are synced by always sending the full content
	 * of the document.
	 */
	export const Full = 1;

	/**
	 * Documents are synced by sending the full content on open.
	 * After that only incremental updates to the document are
	 * send.
	 */
	export const Incremental = 2;
}

export interface TextDocumentSyncOptions {
	/**
	 * Open and close notifications are sent to the server. If omitted open close notification should not
	 * be sent.
	 */
	openClose?: boolean;
	/**
	 * Change notifications are sent to the server. See TextDocumentSyncKind.None, TextDocumentSyncKind.Full
	 * and TextDocumentSyncKind.Incremental. If omitted it defaults to TextDocumentSyncKind.None.
	 */
	change?: number;
	/**
	 * If present will save notifications are sent to the server. If omitted the notification should not be
	 * sent.
	 */
	willSave?: boolean;
	/**
	 * If present will save wait until requests are sent to the server. If omitted the request should not be
	 * sent.
	 */
	willSaveWaitUntil?: boolean;
	/**
	 * If present save notifications are sent to the server. If omitted the notification should not be
	 * sent.
	 */
	save?: SaveOptions;
}

PublishDiagnostics Notification (:arrow_left:)

Diagnostics notification are sent from the server to the client to signal results of validation runs.

Diagnostics are “owned” by the server so it is the server’s responsibility to clear them if necessary. The following rule is used for VS Code servers that generate diagnostics:

  • if a language is single file only (for example HTML) then diagnostics are cleared by the server when the file is closed.
  • if a language has a project system (for example C#) diagnostics are not cleared when a file closes. When a project is opened all diagnostics for all files are recomputed (or read from a cache).

When a file changes it is the server’s responsibility to re-compute diagnostics and push them to the client. If the computed set is empty it has to push the empty array to clear former diagnostics. Newly pushed diagnostics always replace previously pushed diagnostics. There is no merging that happens on the client side.

See also the Diagnostic section.

Client Capability:

  • property name (optional): textDocument.publishDiagnostics
  • property type PublishDiagnosticsClientCapabilities defined as follows:
export interface PublishDiagnosticsClientCapabilities {
	/**
	 * Whether the clients accepts diagnostics with related information.
	 */
	relatedInformation?: boolean;

	/**
	 * Client supports the tag property to provide meta data about a diagnostic.
	 * Clients supporting tags have to handle unknown tags gracefully.
	 *
	 * @since 3.15.0
	 */
	tagSupport?: {
		/**
		 * The tags supported by the client.
		 */
		valueSet: DiagnosticTag[];
	};
}

Notification:

  • method: ‘textDocument/publishDiagnostics’
  • params: PublishDiagnosticsParams defined as follows:
interface PublishDiagnosticsParams {
	/**
	 * The URI for which diagnostic information is reported.
	 */
	uri: DocumentUri;

	/**
	 * Optional the version number of the document the diagnostics are published for.
	 *
	 * @since 3.15.0
	 */
	version?: number;

	/**
	 * An array of diagnostic information items.
	 */
	diagnostics: Diagnostic[];
}

Completion Request (:leftwards_arrow_with_hook:)

The Completion request is sent from the client to the server to compute completion items at a given cursor position. Completion items are presented in the IntelliSense user interface. If computing full completion items is expensive, servers can additionally provide a handler for the completion item resolve request (‘completionItem/resolve’). This request is sent when a completion item is selected in the user interface. A typical use case is for example: the ‘textDocument/completion’ request doesn’t fill in the documentation property for returned completion items since it is expensive to compute. When the item is selected in the user interface then a ‘completionItem/resolve’ request is sent with the selected completion item as a parameter. The returned completion item should have the documentation property filled in. The request can delay the computation of the detail and documentation properties. However, properties that are needed for the initial sorting and filtering, like sortText, filterText, insertText, and textEdit must be provided in the textDocument/completion response and must not be changed during resolve.

Client Capability:

  • property name (optional): textDocument.completion
  • property type: CompletionClientCapabilities defined as follows:
export interface CompletionClientCapabilities {
	/**
	 * Whether completion supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports the following `CompletionItem` specific
	 * capabilities.
	 */
	completionItem?: {
		/**
		 * Client supports snippets as insert text.
		 *
		 * A snippet can define tab stops and placeholders with `$1`, `$2`
		 * and `${3:foo}`. `$0` defines the final tab stop, it defaults to
		 * the end of the snippet. Placeholders with equal identifiers are linked,
		 * that is typing in one will update others too.
		 */
		snippetSupport?: boolean;

		/**
		 * Client supports commit characters on a completion item.
		 */
		commitCharactersSupport?: boolean

		/**
		 * Client supports the follow content formats for the documentation
		 * property. The order describes the preferred format of the client.
		 */
		documentationFormat?: MarkupKind[];

		/**
		 * Client supports the deprecated property on a completion item.
		 */
		deprecatedSupport?: boolean;

		/**
		 * Client supports the preselect property on a completion item.
		 */
		preselectSupport?: boolean;

		/**
		 * Client supports the tag property on a completion item. Clients supporting
		 * tags have to handle unknown tags gracefully. Clients especially need to
		 * preserve unknown tags when sending a completion item back to the server in
		 * a resolve call.
		 *
		 * @since 3.15.0
		 */
		tagSupport?: {
			/**
			 * The tags supported by the client.
			 */
			valueSet: CompletionItemTag[]
		}
	};

	completionItemKind?: {
		/**
		 * The completion item kind values the client supports. When this
		 * property exists the client also guarantees that it will
		 * handle values outside its set gracefully and falls back
		 * to a default value when unknown.
		 *
		 * If this property is not present the client only supports
		 * the completion items kinds from `Text` to `Reference` as defined in
		 * the initial version of the protocol.
		 */
		valueSet?: CompletionItemKind[];
	};

	/**
	 * The client supports to send additional context information for a
	 * `textDocument/completion` requestion.
	 */
	contextSupport?: boolean;
}

Server Capability:

  • property name (optional): completionProvider
  • property type: CompletionOptions defined as follows:
/**
 * Completion options.
 */
export interface CompletionOptions extends WorkDoneProgressOptions {
	/**
	 * Most tools trigger completion request automatically without explicitly requesting
	 * it using a keyboard shortcut (e.g. Ctrl+Space). Typically they do so when the user
	 * starts to type an identifier. For example if the user types `c` in a JavaScript file
	 * code complete will automatically pop up present `console` besides others as a
	 * completion item. Characters that make up identifiers don't need to be listed here.
	 *
	 * If code complete should automatically be trigger on characters not being valid inside
	 * an identifier (for example `.` in JavaScript) list them in `triggerCharacters`.
	 */
	triggerCharacters?: string[];

	/**
	 * The list of all possible characters that commit a completion. This field can be used
	 * if clients don't support individual commmit characters per completion item. See
	 * `ClientCapabilities.textDocument.completion.completionItem.commitCharactersSupport`
	 *
	 * @since 3.2.0
	 */
	allCommitCharacters?: string[];

	/**
	 * The server provides support to resolve additional
	 * information for a completion item.
	 */
	resolveProvider?: boolean;
}

Registration Options: CompletionRegistrationOptions options defined as follows:

export interface CompletionRegistrationOptions extends TextDocumentRegistrationOptions, CompletionOptions {
}

Request:

  • method: ‘textDocument/completion’
  • params: CompletionParams defined as follows:
export interface CompletionParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
	/**
	 * The completion context. This is only available if the client specifies
	 * to send this using `ClientCapabilities.textDocument.completion.contextSupport === true`
	 */
	context?: CompletionContext;
}

/**
 * How a completion was triggered
 */
export namespace CompletionTriggerKind {
	/**
	 * Completion was triggered by typing an identifier (24x7 code
	 * complete), manual invocation (e.g Ctrl+Space) or via API.
	 */
	export const Invoked: 1 = 1;

	/**
	 * Completion was triggered by a trigger character specified by
	 * the `triggerCharacters` properties of the `CompletionRegistrationOptions`.
	 */
	export const TriggerCharacter: 2 = 2;

	/**
	 * Completion was re-triggered as the current completion list is incomplete.
	 */
	export const TriggerForIncompleteCompletions: 3 = 3;
}
export type CompletionTriggerKind = 1 | 2 | 3;


/**
 * Contains additional information about the context in which a completion request is triggered.
 */
export interface CompletionContext {
	/**
	 * How the completion was triggered.
	 */
	triggerKind: CompletionTriggerKind;

	/**
	 * The trigger character (a single character) that has trigger code complete.
	 * Is undefined if `triggerKind !== CompletionTriggerKind.TriggerCharacter`
	 */
	triggerCharacter?: string;
}

Response:

  • result: CompletionItem[] | CompletionList | null. If a CompletionItem[] is provided it is interpreted to be complete. So it is the same as { isIncomplete: false, items }
/**
 * Represents a collection of [completion items](#CompletionItem) to be presented
 * in the editor.
 */
export interface CompletionList {
	/**
	 * This list it not complete. Further typing should result in recomputing
	 * this list.
	 */
	isIncomplete: boolean;

	/**
	 * The completion items.
	 */
	items: CompletionItem[];
}

/**
 * Defines whether the insert text in a completion item should be interpreted as
 * plain text or a snippet.
 */
export namespace InsertTextFormat {
	/**
	 * The primary text to be inserted is treated as a plain string.
	 */
	export const PlainText = 1;

	/**
	 * The primary text to be inserted is treated as a snippet.
	 *
	 * A snippet can define tab stops and placeholders with `$1`, `$2`
	 * and `${3:foo}`. `$0` defines the final tab stop, it defaults to
	 * the end of the snippet. Placeholders with equal identifiers are linked,
	 * that is typing in one will update others too.
	 */
	export const Snippet = 2;
}

export type InsertTextFormat = 1 | 2;

/**
 * Completion item tags are extra annotations that tweak the rendering of a completion
 * item.
 *
 * @since 3.15.0
 */
export namespace CompletionItemTag {
	/**
	 * Render a completion as obsolete, usually using a strike-out.
	 */
	export const Deprecated = 1;
}

export type CompletionItemTag = 1;

export interface CompletionItem {
	/**
	 * The label of this completion item. By default
	 * also the text that is inserted when selecting
	 * this completion.
	 */
	label: string;

	/**
	 * The kind of this completion item. Based of the kind
	 * an icon is chosen by the editor. The standardized set
	 * of available values is defined in `CompletionItemKind`.
	 */
	kind?: number;

	/**
	 * Tags for this completion item.
	 *
	 * @since 3.15.0
	 */
	tags?: CompletionItemTag[];

	/**
	 * A human-readable string with additional information
	 * about this item, like type or symbol information.
	 */
	detail?: string;

	/**
	 * A human-readable string that represents a doc-comment.
	 */
	documentation?: string | MarkupContent;

	/**
	 * Indicates if this item is deprecated.
	 */
	deprecated?: boolean;

	/**
	 * Select this item when showing.
	 *
	 * *Note* that only one completion item can be selected and that the
	 * tool / client decides which item that is. The rule is that the *first*
	 * item of those that match best is selected.
	 */
	preselect?: boolean;

	/**
	 * A string that should be used when comparing this item
	 * with other items. When `falsy` the label is used.
	 */
	sortText?: string;

	/**
	 * A string that should be used when filtering a set of
	 * completion items. When `falsy` the label is used.
	 */
	filterText?: string;

	/**
	 * A string that should be inserted into a document when selecting
	 * this completion. When `falsy` the label is used.
	 *
	 * The `insertText` is subject to interpretation by the client side.
	 * Some tools might not take the string literally. For example
	 * VS Code when code complete is requested in this example `con<cursor position>`
	 * and a completion item with an `insertText` of `console` is provided it
	 * will only insert `sole`. Therefore it is recommended to use `textEdit` instead
	 * since it avoids additional client side interpretation.
	 */
	insertText?: string;

	/**
	 * The format of the insert text. The format applies to both the `insertText` property
	 * and the `newText` property of a provided `textEdit`.
	 */
	insertTextFormat?: InsertTextFormat;

	/**
	 * An edit which is applied to a document when selecting this completion. When an edit is provided the value of
	 * `insertText` is ignored.
	 *
	 * *Note:* The range of the edit must be a single line range and it must contain the position at which completion
	 * has been requested.
	 */
	textEdit?: TextEdit;

	/**
	 * An optional array of additional text edits that are applied when
	 * selecting this completion. Edits must not overlap (including the same insert position)
	 * with the main edit nor with themselves.
	 *
	 * Additional text edits should be used to change text unrelated to the current cursor position
	 * (for example adding an import statement at the top of the file if the completion item will
	 * insert an unqualified type).
	 */
	additionalTextEdits?: TextEdit[];

	/**
	 * An optional set of characters that when pressed while this completion is active will accept it first and
	 * then type that character. *Note* that all commit characters should have `length=1` and that superfluous
	 * characters will be ignored.
	 */
	commitCharacters?: string[];

	/**
	 * An optional command that is executed *after* inserting this completion. *Note* that
	 * additional modifications to the current document should be described with the
	 * additionalTextEdits-property.
	 */
	command?: Command;

	/**
	 * A data entry field that is preserved on a completion item between
	 * a completion and a completion resolve request.
	 */
	data?: any
}

/**
 * The kind of a completion entry.
 */
export namespace CompletionItemKind {
	export const Text = 1;
	export const Method = 2;
	export const Function = 3;
	export const Constructor = 4;
	export const Field = 5;
	export const Variable = 6;
	export const Class = 7;
	export const Interface = 8;
	export const Module = 9;
	export const Property = 10;
	export const Unit = 11;
	export const Value = 12;
	export const Enum = 13;
	export const Keyword = 14;
	export const Snippet = 15;
	export const Color = 16;
	export const File = 17;
	export const Reference = 18;
	export const Folder = 19;
	export const EnumMember = 20;
	export const Constant = 21;
	export const Struct = 22;
	export const Event = 23;
	export const Operator = 24;
	export const TypeParameter = 25;
}
  • partial result: CompletionItem[]
  • error: code and message set in case an exception happens during the completion request.

Completion items support snippets (see InsertTextFormat.Snippet). The snippet format is as follows:

Snippet Syntax

The body of a snippet can use special constructs to control cursors and the text being inserted. The following are supported features and their syntaxes:

Tab stops

With tab stops, you can make the editor cursor move inside a snippet. Use $1, $2 to specify cursor locations. The number is the order in which tab stops will be visited, whereas $0 denotes the final cursor position. Multiple tab stops are linked and updated in sync.

Placeholders

Placeholders are tab stops with values, like ${1:foo}. The placeholder text will be inserted and selected such that it can be easily changed. Placeholders can be nested, like ${1:another ${2:placeholder}}.

Choice

Placeholders can have choices as values. The syntax is a comma separated enumeration of values, enclosed with the pipe-character, for example ${1|one,two,three|}. When the snippet is inserted and the placeholder selected, choices will prompt the user to pick one of the values.

Variables

With $name or ${name:default} you can insert the value of a variable. When a variable isn’t set, its default or the empty string is inserted. When a variable is unknown (that is, its name isn’t defined) the name of the variable is inserted and it is transformed into a placeholder.

The following variables can be used:

  • TM_SELECTED_TEXT The currently selected text or the empty string
  • TM_CURRENT_LINE The contents of the current line
  • TM_CURRENT_WORD The contents of the word under cursor or the empty string
  • TM_LINE_INDEX The zero-index based line number
  • TM_LINE_NUMBER The one-index based line number
  • TM_FILENAME The filename of the current document
  • TM_FILENAME_BASE The filename of the current document without its extensions
  • TM_DIRECTORY The directory of the current document
  • TM_FILEPATH The full file path of the current document
Variable Transforms

Transformations allow you to modify the value of a variable before it is inserted. The definition of a transformation consists of three parts:

  1. A regular expression that is matched against the value of a variable, or the empty string when the variable cannot be resolved.
  2. A “format string” that allows to reference matching groups from the regular expression. The format string allows for conditional inserts and simple modifications.
  3. Options that are passed to the regular expression.

The following example inserts the name of the current file without its ending, so from foo.txt it makes foo.

${TM_FILENAME/(.*)\..+$/$1/}
  |           |         | |
  |           |         | |-> no options
  |           |         |
  |           |         |-> references the contents of the first
  |           |             capture group
  |           |
  |           |-> regex to capture everything before
  |               the final `.suffix`
  |
  |-> resolves to the filename
Grammar

Below is the EBNF (extended Backus-Naur form) for snippets. With \ (backslash), you can escape $, } and \. Within choice elements, the backslash also escapes comma and pipe characters.

any         ::= tabstop | placeholder | choice | variable | text
tabstop     ::= '$' int | '${' int '}'
placeholder ::= '${' int ':' any '}'
choice      ::= '${' int '|' text (',' text)* '|}'
variable    ::= '$' var | '${' var }'
                | '${' var ':' any '}'
                | '${' var '/' regex '/' (format | text)+ '/' options '}'
format      ::= '$' int | '${' int '}'
                | '${' int ':' '/upcase' | '/downcase' | '/capitalize' '}'
                | '${' int ':+' if '}'
                | '${' int ':?' if ':' else '}'
                | '${' int ':-' else '}' | '${' int ':' else '}'
regex       ::= JavaScript Regular Expression value (ctor-string)
options     ::= JavaScript Regular Expression option (ctor-options)
var         ::= [_a-zA-Z] [_a-zA-Z0-9]*
int         ::= [0-9]+
text        ::= .*

Completion Item Resolve Request (:leftwards_arrow_with_hook:)

The request is sent from the client to the server to resolve additional information for a given completion item.

Request:

  • method: ‘completionItem/resolve’
  • params: CompletionItem

Response:

  • result: CompletionItem
  • error: code and message set in case an exception happens during the completion resolve request.

Hover Request (:leftwards_arrow_with_hook:)

The hover request is sent from the client to the server to request hover information at a given text document position.

Client Capability:

  • property name (optional): textDocument.hover
  • property type: HoverClientCapabilities defined as follows:
export interface HoverClientCapabilities {
	/**
	 * Whether hover supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * Client supports the follow content formats for the content
	 * property. The order describes the preferred format of the client.
	 */
	contentFormat?: MarkupKind[];
}

Server Capability:

  • property name (optional): hoverProvider
  • property type: boolean | HoverOptions were HoverOptions is defined as follows:
export interface HoverOptions extends WorkDoneProgressOptions {
}

Registration Options: HoverRegistrationOptions defined as follows:

export interface HoverRegistrationOptions extends TextDocumentRegistrationOptions, HoverOptions {
}

Request:

  • method: ‘textDocument/hover’
  • params: HoverParams defined as follows:
export interface HoverParams extends TextDocumentPositionParams, WorkDoneProgressParams {
}

Response:

  • result: Hover | null defined as follows:
/**
 * The result of a hover request.
 */
export interface Hover {
	/**
	 * The hover's content
	 */
	contents: MarkedString | MarkedString[] | MarkupContent;

	/**
	 * An optional range is a range inside a text document
	 * that is used to visualize a hover, e.g. by changing the background color.
	 */
	range?: Range;
}

Where MarkedString is defined as follows:

/**
 * MarkedString can be used to render human readable text. It is either a markdown string
 * or a code-block that provides a language and a code snippet. The language identifier
 * is semantically equal to the optional language identifier in fenced code blocks in GitHub
 * issues. See https://help.github.com/articles/creating-and-highlighting-code-blocks/#syntax-highlighting
 *
 * The pair of a language and a value is an equivalent to markdown:
 * ```${language}
 * ${value}
 * ```
 *
 * Note that markdown strings will be sanitized - that means html will be escaped.
* @deprecated use MarkupContent instead.
*/
type MarkedString = string | { language: string; value: string };
  • error: code and message set in case an exception happens during the hover request.

Signature Help Request (:leftwards_arrow_with_hook:)

The signature help request is sent from the client to the server to request signature information at a given cursor position.

Client Capability:

  • property name (optional): textDocument.signatureHelp
  • property type: SignatureHelpClientCapabilities defined as follows:
export interface SignatureHelpClientCapabilities {
	/**
	 * Whether signature help supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports the following `SignatureInformation`
	 * specific properties.
	 */
	signatureInformation?: {
		/**
		 * Client supports the follow content formats for the documentation
		 * property. The order describes the preferred format of the client.
		 */
		documentationFormat?: MarkupKind[];

		/**
		 * Client capabilities specific to parameter information.
		 */
		parameterInformation?: {
			/**
			 * The client supports processing label offsets instead of a
			 * simple label string.
			 *
			 * @since 3.14.0
			 */
			labelOffsetSupport?: boolean;
		};
	};

	/**
	 * The client supports to send additional context information for a
	 * `textDocument/signatureHelp` request. A client that opts into
	 * contextSupport will also support the `retriggerCharacters` on
	 * `SignatureHelpOptions`.
	 *
	 * @since 3.15.0
	 */
	contextSupport?: boolean;
}

Server Capability:

  • property name (optional): signatureHelpProvider
  • property type: SignatureHelpOptions defined as follows:
export interface SignatureHelpOptions extends WorkDoneProgressOptions {
	/**
	 * The characters that trigger signature help
	 * automatically.
	 */
	triggerCharacters?: string[];

	/**
	 * List of characters that re-trigger signature help.
	 *
	 * These trigger characters are only active when signature help is already showing. All trigger characters
	 * are also counted as re-trigger characters.
	 *
	 * @since 3.15.0
	 */
	retriggerCharacters?: string[];
}

Registration Options: SignatureHelpRegistrationOptions defined as follows:

export interface SignatureHelpRegistrationOptions extends TextDocumentRegistrationOptions, SignatureHelpOptions {
}

Request:

  • method: ‘textDocument/signatureHelp’
  • params: SignatureHelpParams defined as follows:
export interface SignatureHelpParams extends TextDocumentPositionParams, WorkDoneProgressParams {
	/**
	 * The signature help context. This is only available if the client specifies
	 * to send this using the client capability  `textDocument.signatureHelp.contextSupport === true`
	 *
	 * @since 3.15.0
	 */
	context?: SignatureHelpContext;
}

/**
 * How a signature help was triggered.
 *
 * @since 3.15.0
 */
export namespace SignatureHelpTriggerKind {
	/**
	 * Signature help was invoked manually by the user or by a command.
	 */
	export const Invoked: 1 = 1;
	/**
	 * Signature help was triggered by a trigger character.
	 */
	export const TriggerCharacter: 2 = 2;
	/**
	 * Signature help was triggered by the cursor moving or by the document content changing.
	 */
	export const ContentChange: 3 = 3;
}
export type SignatureHelpTriggerKind = 1 | 2 | 3;

/**
 * Additional information about the context in which a signature help request was triggered.
 *
 * @since 3.15.0
 */
export interface SignatureHelpContext {
	/**
	 * Action that caused signature help to be triggered.
	 */
	triggerKind: SignatureHelpTriggerKind;

	/**
	 * Character that caused signature help to be triggered.
	 *
	 * This is undefined when `triggerKind !== SignatureHelpTriggerKind.TriggerCharacter`
	 */
	triggerCharacter?: string;

	/**
	 * `true` if signature help was already showing when it was triggered.
	 *
	 * Retriggers occur when the signature help is already active and can be caused by actions such as
	 * typing a trigger character, a cursor move, or document content changes.
	 */
	isRetrigger: boolean;

	/**
	 * The currently active `SignatureHelp`.
	 *
	 * The `activeSignatureHelp` has its `SignatureHelp.activeSignature` field updated based on
	 * the user navigating through available signatures.
	 */
	activeSignatureHelp?: SignatureHelp;
}

Response:

  • result: SignatureHelp | null defined as follows:
/**
 * Signature help represents the signature of something
 * callable. There can be multiple signature but only one
 * active and only one active parameter.
 */
export interface SignatureHelp {
	/**
	 * One or more signatures.
	 */
	signatures: SignatureInformation[];

	/**
	 * The active signature. If omitted or the value lies outside the
	 * range of `signatures` the value defaults to zero or is ignored if
	 * `signatures.length === 0`. Whenever possible implementors should
	 * make an active decision about the active signature and shouldn't
	 * rely on a default value.
	 * In future version of the protocol this property might become
	 * mandatory to better express this.
	 */
	activeSignature?: number;

	/**
	 * The active parameter of the active signature. If omitted or the value
	 * lies outside the range of `signatures[activeSignature].parameters`
	 * defaults to 0 if the active signature has parameters. If
	 * the active signature has no parameters it is ignored.
	 * In future version of the protocol this property might become
	 * mandatory to better express the active parameter if the
	 * active signature does have any.
	 */
	activeParameter?: number;
}

/**
 * Represents the signature of something callable. A signature
 * can have a label, like a function-name, a doc-comment, and
 * a set of parameters.
 */
export interface SignatureInformation {
	/**
	 * The label of this signature. Will be shown in
	 * the UI.
	 */
	label: string;

	/**
	 * The human-readable doc-comment of this signature. Will be shown
	 * in the UI but can be omitted.
	 */
	documentation?: string | MarkupContent;

	/**
	 * The parameters of this signature.
	 */
	parameters?: ParameterInformation[];
}

/**
 * Represents a parameter of a callable-signature. A parameter can
 * have a label and a doc-comment.
 */
export interface ParameterInformation {

	/**
	 * The label of this parameter information.
	 *
	 * Either a string or an inclusive start and exclusive end offsets within its containing
	 * signature label. (see SignatureInformation.label). The offsets are based on a UTF-16
	 * string representation as `Position` and `Range` does.
	 *
	 * *Note*: a label of type string should be a substring of its containing signature label.
	 * Its intended use case is to highlight the parameter label part in the `SignatureInformation.label`.
	 */
	label: string | [number, number];

	/**
	 * The human-readable doc-comment of this parameter. Will be shown
	 * in the UI but can be omitted.
	 */
	documentation?: string | MarkupContent;
}
  • error: code and message set in case an exception happens during the signature help request.

Goto Declaration Request (:leftwards_arrow_with_hook:)

Since version 3.14.0

The go to declaration request is sent from the client to the server to resolve the declaration location of a symbol at a given text document position.

The result type LocationLink[] got introduce with version 3.14.0 and depends on the corresponding client capability textDocument.declaration.linkSupport.

Client Capability:

  • property name (optional): textDocument.declaration
  • property type: DeclarationClientCapabilities defined as follows:
export interface DeclarationClientCapabilities {
	/**
	 * Whether declaration supports dynamic registration. If this is set to `true`
	 * the client supports the new `DeclarationRegistrationOptions` return value
	 * for the corresponding server capability as well.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports additional metadata in the form of declaration links.
	 */
	linkSupport?: boolean;
}

Server Capability:

  • property name (optional): declarationProvider
  • property type: boolean | DeclarationOptions | DeclarationRegistrationOptions were DeclarationOptions is defined as follows:
export interface DeclarationOptions extends WorkDoneProgressOptions {
}

Registration Options: DeclarationRegistrationOptions defined as follows:

export interface DeclarationRegistrationOptions extends DeclarationOptions, TextDocumentRegistrationOptions, StaticRegistrationOptions  {
}

Request:

  • method: ‘textDocument/declaration’
  • params: DeclarationParams defined as follows:
export interface DeclarationParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
}

Response:

Goto Definition Request (:leftwards_arrow_with_hook:)

The go to definition request is sent from the client to the server to resolve the definition location of a symbol at a given text document position. ` The result type LocationLink[] got introduce with version 3.14.0 and depends in the corresponding client capability textDocument.definition.linkSupport.

Client Capability:

  • property name (optional): textDocument.definition
  • property type: DefinitionClientCapabilities defined as follows:
export interface DefinitionClientCapabilities {
	/**
	 * Whether definition supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports additional metadata in the form of definition links.
	 *
	 * @since 3.14.0
	 */
	linkSupport?: boolean;
}

Server Capability:

  • property name (optional): definitionProvider
  • property type: boolean | DefinitionOptions were DefinitionOptions is defined as follows:
export interface DefinitionOptions extends WorkDoneProgressOptions {
}

Registration Options: DefinitionRegistrationOptions defined as follows:

export interface DefinitionRegistrationOptions extends TextDocumentRegistrationOptions, DefinitionOptions {
}

Request:

  • method: ‘textDocument/definition’
  • params: DefinitionParams defined as follows:
export interface DefinitionParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
}

Response:

Goto Type Definition Request (:leftwards_arrow_with_hook:)

Since version 3.6.0

The go to type definition request is sent from the client to the server to resolve the type definition location of a symbol at a given text document position.

The result type LocationLink[] got introduce with version 3.14.0 and depends in the corresponding client capability textDocument.typeDefinition.linkSupport.

Client Capability:

  • property name (optional): textDocument.typeDefinition
  • property type: DefinitionClientCapabilities defined as follows:
export interface TypeDefinitionClientCapabilities {
	/**
	 * Whether implementation supports dynamic registration. If this is set to `true`
	 * the client supports the new `TypeDefinitionRegistrationOptions` return value
	 * for the corresponding server capability as well.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports additional metadata in the form of definition links.
	 *
	 * @since 3.14.0
	 */
	linkSupport?: boolean;
}

Server Capability:

  • property name (optional): typeDefinitionProvider
  • property type: boolean | TypeDefinitionOptions | TypeDefinitionRegistrationOptions were TypeDefinitionOptions is defined as follows:
export interface TypeDefinitionOptions extends WorkDoneProgressOptions {
}

Registration Options: TypeDefinitionRegistrationOptions defined as follows:

export interface TypeDefinitionRegistrationOptions extends TextDocumentRegistrationOptions, TypeDefinitionOptions, StaticRegistrationOptions {
}

Request:

  • method: ‘textDocument/typeDefinition’
  • params: TypeDefinitionParams defined as follows:
export interface TypeDefinitionParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
}

Response:

Goto Implementation Request (:leftwards_arrow_with_hook:)

Since version 3.6.0

The go to implementation request is sent from the client to the server to resolve the implementation location of a symbol at a given text document position.

The result type LocationLink[] got introduce with version 3.14.0 and depends in the corresponding client capability implementation.typeDefinition.linkSupport.

Client Capability:

  • property name (optional): textDocument.implementation
  • property type: ImplementationClientCapabilities defined as follows:
export interface ImplementationClientCapabilities {
	/**
	 * Whether implementation supports dynamic registration. If this is set to `true`
	 * the client supports the new `ImplementationRegistrationOptions` return value
	 * for the corresponding server capability as well.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client supports additional metadata in the form of definition links.
	 *
	 * @since 3.14.0
	 */
	linkSupport?: boolean;
}

Server Capability:

  • property name (optional): implementationProvider
  • property type: boolean | ImplementationOptions | ImplementationRegistrationOptions were ImplementationOptions is defined as follows:
export interface ImplementationOptions extends WorkDoneProgressOptions {
}

Registration Options: ImplementationRegistrationOptions defined as follows:

export interface ImplementationRegistrationOptions extends TextDocumentRegistrationOptions, ImplementationOptions, StaticRegistrationOptions {
}

Request:

  • method: ‘textDocument/implementation’
  • params: ImplementationParams defined as follows:
export interface ImplementationParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
}

Response:

Find References Request (:leftwards_arrow_with_hook:)

The references request is sent from the client to the server to resolve project-wide references for the symbol denoted by the given text document position.

Client Capability:

  • property name (optional): textDocument.references
  • property type: ReferenceClientCapabilities defined as follows:
export interface ReferenceClientCapabilities {
	/**
	 * Whether references supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): referencesProvider
  • property type: boolean | ReferenceOptions were ReferenceOptions is defined as follows:
export interface ReferenceOptions extends WorkDoneProgressOptions {
}

Registration Options: ReferenceRegistrationOptions defined as follows:

export interface ReferenceRegistrationOptions extends TextDocumentRegistrationOptions, ReferenceOptions {
}

Request:

  • method: ‘textDocument/references’
  • params: ReferenceParams defined as follows:
export interface ReferenceParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
	context: ReferenceContext
}

export interface ReferenceContext {
	/**
	 * Include the declaration of the current symbol.
	 */
	includeDeclaration: boolean;
}

Response:

  • result: Location[] | null
  • partial result: Location[]
  • error: code and message set in case an exception happens during the reference request.

Document Highlights Request (:leftwards_arrow_with_hook:)

The document highlight request is sent from the client to the server to resolve a document highlights for a given text document position. For programming languages this usually highlights all references to the symbol scoped to this file. However we kept ‘textDocument/documentHighlight’ and ‘textDocument/references’ separate requests since the first one is allowed to be more fuzzy. Symbol matches usually have a DocumentHighlightKind of Read or Write whereas fuzzy or textual matches use Textas the kind.

Client Capability:

  • property name (optional): textDocument.documentHighlight
  • property type: DocumentHighlightClientCapabilities defined as follows:
export interface DocumentHighlightClientCapabilities {
	/**
	 * Whether document highlight supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): documentHighlightProvider
  • property type: boolean | DocumentHighlightOptions were DocumentHighlightOptions is defined as follows:
export interface DocumentHighlightOptions extends WorkDoneProgressOptions {
}

Registration Options: DocumentHighlightRegistrationOptions defined as follows:

export interface DocumentHighlightRegistrationOptions extends TextDocumentRegistrationOptions, DocumentHighlightOptions {
}

Request:

  • method: ‘textDocument/documentHighlight’
  • params: DocumentHighlightParams defined as follows:
export interface DocumentHighlightParams extends TextDocumentPositionParams, WorkDoneProgressParams, PartialResultParams {
}

Response:

  • result: DocumentHighlight[] | null defined as follows:
/**
 * A document highlight is a range inside a text document which deserves
 * special attention. Usually a document highlight is visualized by changing
 * the background color of its range.
 *
 */
export interface DocumentHighlight {
	/**
	 * The range this highlight applies to.
	 */
	range: Range;

	/**
	 * The highlight kind, default is DocumentHighlightKind.Text.
	 */
	kind?: number;
}

/**
 * A document highlight kind.
 */
export namespace DocumentHighlightKind {
	/**
	 * A textual occurrence.
	 */
	export const Text = 1;

	/**
	 * Read-access of a symbol, like reading a variable.
	 */
	export const Read = 2;

	/**
	 * Write-access of a symbol, like writing to a variable.
	 */
	export const Write = 3;
}
  • partial result: DocumentHighlight[]
  • error: code and message set in case an exception happens during the document highlight request.

Document Symbols Request (:leftwards_arrow_with_hook:)

The document symbol request is sent from the client to the server. The returned result is either

  • SymbolInformation[] which is a flat list of all symbols found in a given text document. Then neither the symbol’s location range nor the symbol’s container name should be used to infer a hierarchy.
  • DocumentSymbol[] which is a hierarchy of symbols found in a given text document.

Client Capability:

  • property name (optional): textDocument.documentSymbol
  • property type: DocumentSymbolClientCapabilities defined as follows:
export interface DocumentHighlightClientCapabilities {
	/**
	 * Whether document highlight supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): documentSymbolProvider
  • property type: boolean | DocumentSymbolOptions were DocumentSymbolOptions is defined as follows:
export interface DocumentSymbolOptions extends WorkDoneProgressOptions {
}

Registration Options: DocumentSymbolRegistrationOptions defined as follows:

export interface DocumentSymbolRegistrationOptions extends TextDocumentRegistrationOptions, DocumentSymbolOptions {
}

Request:

  • method: ‘textDocument/documentSymbol’
  • params: DocumentSymbolParams defined as follows:
export interface DocumentSymbolParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;
}

Response:

  • result: DocumentSymbol[] | SymbolInformation[] | null defined as follows:
/**
 * A symbol kind.
 */
export namespace SymbolKind {
	export const File = 1;
	export const Module = 2;
	export const Namespace = 3;
	export const Package = 4;
	export const Class = 5;
	export const Method = 6;
	export const Property = 7;
	export const Field = 8;
	export const Constructor = 9;
	export const Enum = 10;
	export const Interface = 11;
	export const Function = 12;
	export const Variable = 13;
	export const Constant = 14;
	export const String = 15;
	export const Number = 16;
	export const Boolean = 17;
	export const Array = 18;
	export const Object = 19;
	export const Key = 20;
	export const Null = 21;
	export const EnumMember = 22;
	export const Struct = 23;
	export const Event = 24;
	export const Operator = 25;
	export const TypeParameter = 26;
}

/**
 * Represents programming constructs like variables, classes, interfaces etc. that appear in a document. Document symbols can be
 * hierarchical and they have two ranges: one that encloses its definition and one that points to its most interesting range,
 * e.g. the range of an identifier.
 */
export interface DocumentSymbol {

	/**
	 * The name of this symbol. Will be displayed in the user interface and therefore must not be
	 * an empty string or a string only consisting of white spaces.
	 */
	name: string;

	/**
	 * More detail for this symbol, e.g the signature of a function.
	 */
	detail?: string;

	/**
	 * The kind of this symbol.
	 */
	kind: SymbolKind;

	/**
	 * Indicates if this symbol is deprecated.
	 */
	deprecated?: boolean;

	/**
	 * The range enclosing this symbol not including leading/trailing whitespace but everything else
	 * like comments. This information is typically used to determine if the clients cursor is
	 * inside the symbol to reveal in the symbol in the UI.
	 */
	range: Range;

	/**
	 * The range that should be selected and revealed when this symbol is being picked, e.g the name of a function.
	 * Must be contained by the `range`.
	 */
	selectionRange: Range;

	/**
	 * Children of this symbol, e.g. properties of a class.
	 */
	children?: DocumentSymbol[];
}

/**
 * Represents information about programming constructs like variables, classes,
 * interfaces etc.
 */
export interface SymbolInformation {
	/**
	 * The name of this symbol.
	 */
	name: string;

	/**
	 * The kind of this symbol.
	 */
	kind: number;

	/**
	 * Indicates if this symbol is deprecated.
	 */
	deprecated?: boolean;

	/**
	 * The location of this symbol. The location's range is used by a tool
	 * to reveal the location in the editor. If the symbol is selected in the
	 * tool the range's start information is used to position the cursor. So
	 * the range usually spans more then the actual symbol's name and does
	 * normally include things like visibility modifiers.
	 *
	 * The range doesn't have to denote a node range in the sense of a abstract
	 * syntax tree. It can therefore not be used to re-construct a hierarchy of
	 * the symbols.
	 */
	location: Location;

	/**
	 * The name of the symbol containing this symbol. This information is for
	 * user interface purposes (e.g. to render a qualifier in the user interface
	 * if necessary). It can't be used to re-infer a hierarchy for the document
	 * symbols.
	 */
	containerName?: string;
}
  • partial result: DocumentSymbol[] | SymbolInformation[]
  • error: code and message set in case an exception happens during the document symbol request.

Code Action Request (:leftwards_arrow_with_hook:)

The code action request is sent from the client to the server to compute commands for a given text document and range. These commands are typically code fixes to either fix problems or to beautify/refactor code. The result of a textDocument/codeAction request is an array of Command literals which are typically presented in the user interface. To ensure that a server is useful in many clients the commands specified in a code actions should be handled by the server and not by the client (see workspace/executeCommand and ServerCapabilities.executeCommandProvider). If the client supports providing edits with a code action then the mode should be used.

When the command is selected the server should be contacted again (via the workspace/executeCommand) request to execute the command.

Since version 3.8.0: support for CodeAction literals to enable the following scenarios:

  • the ability to directly return a workspace edit from the code action request. This avoids having another server roundtrip to execute an actual code action. However server providers should be aware that if the code action is expensive to compute or the edits are huge it might still be beneficial if the result is simply a command and the actual edit is only computed when needed.
  • the ability to group code actions using a kind. Clients are allowed to ignore that information. However it allows them to better group code action for example into corresponding menus (e.g. all refactor code actions into a refactor menu).

Clients need to announce their support for code action literals and code action kinds via the corresponding client capability codeAction.codeActionLiteralSupport.

Client Capability:

  • property name (optional): textDocument.codeAction
  • property type: CodeActionClientCapabilities defined as follows:
export interface CodeActionClientCapabilities {
	/**
	 * Whether code action supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * The client support code action literals as a valid
	 * response of the `textDocument/codeAction` request.
	 *
	 * @since 3.8.0
	 */
	codeActionLiteralSupport?: {
		/**
		 * The code action kind is support with the following value
		 * set.
		 */
		codeActionKind: {

			/**
			 * The code action kind values the client supports. When this
			 * property exists the client also guarantees that it will
			 * handle values outside its set gracefully and falls back
			 * to a default value when unknown.
			 */
			valueSet: CodeActionKind[];
		};
	};

	/**
	 * Whether code action supports the `isPreferred` property.
	 * @since 3.15.0
	 */
	isPreferredSupport?: boolean;
}

Server Capability:

  • property name (optional): codeActionProvider
  • property type: boolean | CodeActionOptions were CodeActionOptions is defined as follows:
export interface CodeActionOptions extends WorkDoneProgressOptions {
	/**
	 * CodeActionKinds that this server may return.
	 *
	 * The list of kinds may be generic, such as `CodeActionKind.Refactor`, or the server
	 * may list out every specific kind they provide.
	 */
	codeActionKinds?: CodeActionKind[];
}

Registration Options: CodeActionRegistrationOptions defined as follows:

export interface CodeActionRegistrationOptions extends TextDocumentRegistrationOptions, CodeActionOptions {
}

Request:

  • method: ‘textDocument/codeAction’
  • params: CodeActionParams defined as follows:
/**
 * Params for the CodeActionRequest
 */
export interface CodeActionParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The document in which the command was invoked.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The range for which the command was invoked.
	 */
	range: Range;

	/**
	 * Context carrying additional information.
	 */
	context: CodeActionContext;
}

/**
 * The kind of a code action.
 *
 * Kinds are a hierarchical list of identifiers separated by `.`, e.g. `"refactor.extract.function"`.
 *
 * The set of kinds is open and client needs to announce the kinds it supports to the server during
 * initialization.
 */
export type CodeActionKind = string;

/**
 * A set of predefined code action kinds
 */
export namespace CodeActionKind {

	/**
	 * Empty kind.
	 */
	export const Empty: CodeActionKind = '';

	/**
	 * Base kind for quickfix actions: 'quickfix'
	 */
	export const QuickFix: CodeActionKind = 'quickfix';

	/**
	 * Base kind for refactoring actions: 'refactor'
	 */
	export const Refactor: CodeActionKind = 'refactor';

	/**
	 * Base kind for refactoring extraction actions: 'refactor.extract'
	 *
	 * Example extract actions:
	 *
	 * - Extract method
	 * - Extract function
	 * - Extract variable
	 * - Extract interface from class
	 * - ...
	 */
	export const RefactorExtract: CodeActionKind = 'refactor.extract';

	/**
	 * Base kind for refactoring inline actions: 'refactor.inline'
	 *
	 * Example inline actions:
	 *
	 * - Inline function
	 * - Inline variable
	 * - Inline constant
	 * - ...
	 */
	export const RefactorInline: CodeActionKind = 'refactor.inline';

	/**
	 * Base kind for refactoring rewrite actions: 'refactor.rewrite'
	 *
	 * Example rewrite actions:
	 *
	 * - Convert JavaScript function to class
	 * - Add or remove parameter
	 * - Encapsulate field
	 * - Make method static
	 * - Move method to base class
	 * - ...
	 */
	export const RefactorRewrite: CodeActionKind = 'refactor.rewrite';

	/**
	 * Base kind for source actions: `source`
	 *
	 * Source code actions apply to the entire file.
	 */
	export const Source: CodeActionKind = 'source';

	/**
	 * Base kind for an organize imports source action: `source.organizeImports`
	 */
	export const SourceOrganizeImports: CodeActionKind = 'source.organizeImports';
}

/**
 * Contains additional diagnostic information about the context in which
 * a code action is run.
 */
export interface CodeActionContext {
	/**
	 * An array of diagnostics known on the client side overlapping the range provided to the
	 * `textDocument/codeAction` request. They are provied so that the server knows which
	 * errors are currently presented to the user for the given range. There is no guarantee
	 * that these accurately reflect the error state of the resource. The primary parameter
	 * to compute code actions is the provided range.
	 */
	diagnostics: Diagnostic[];

	/**
	 * Requested kind of actions to return.
	 *
	 * Actions not of this kind are filtered out by the client before being shown. So servers
	 * can omit computing them.
	 */
	only?: CodeActionKind[];
}

Response:

  • result: (Command | CodeAction)[] | null where CodeAction is defined as follows:
/**
 * A code action represents a change that can be performed in code, e.g. to fix a problem or
 * to refactor code.
 *
 * A CodeAction must set either `edit` and/or a `command`. If both are supplied, the `edit` is applied first, then the `command` is executed.
 */
export interface CodeAction {

	/**
	 * A short, human-readable, title for this code action.
	 */
	title: string;

	/**
	 * The kind of the code action.
	 *
	 * Used to filter code actions.
	 */
	kind?: CodeActionKind;

	/**
	 * The diagnostics that this code action resolves.
	 */
	diagnostics?: Diagnostic[];

	/**
	 * Marks this as a preferred action. Preferred actions are used by the `auto fix` command and can be targeted
	 * by keybindings.
	 *
	 * A quick fix should be marked preferred if it properly addresses the underlying error.
	 * A refactoring should be marked preferred if it is the most reasonable choice of actions to take.
	 *
	 * @since 3.15.0
	 */
	isPreferred?: boolean;

	/**
	 * The workspace edit this code action performs.
	 */
	edit?: WorkspaceEdit;

	/**
	 * A command this code action executes. If a code action
	 * provides an edit and a command, first the edit is
	 * executed and then the command.
	 */
	command?: Command;
}
  • partial result: (Command | CodeAction)[]
  • error: code and message set in case an exception happens during the code action request.

Code Lens Request (:leftwards_arrow_with_hook:)

The code lens request is sent from the client to the server to compute code lenses for a given text document.

Client Capability:

  • property name (optional): textDocument.codeLens
  • property type: CodeLensClientCapabilities defined as follows:
export interface CodeLensClientCapabilities {
	/**
	 * Whether code lens supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): codeLensProvider
  • property type: CodeLensOptions defined as follows:
export interface CodeLensOptions extends WorkDoneProgressOptions {
	/**
	 * Code lens has a resolve provider as well.
	 */
	resolveProvider?: boolean;
}

Registration Options: CodeLensRegistrationOptions defined as follows:

export interface CodeLensRegistrationOptions extends TextDocumentRegistrationOptions, CodeLensOptions {
}

Request:

  • method: ‘textDocument/codeLens’
  • params: CodeLensParams defined as follows:
interface CodeLensParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The document to request code lens for.
	 */
	textDocument: TextDocumentIdentifier;
}

Response:

  • result: CodeLens[] | null defined as follows:
/**
 * A code lens represents a command that should be shown along with
 * source text, like the number of references, a way to run tests, etc.
 *
 * A code lens is _unresolved_ when no command is associated to it. For performance
 * reasons the creation of a code lens and resolving should be done in two stages.
 */
interface CodeLens {
	/**
	 * The range in which this code lens is valid. Should only span a single line.
	 */
	range: Range;

	/**
	 * The command this code lens represents.
	 */
	command?: Command;

	/**
	 * A data entry field that is preserved on a code lens item between
	 * a code lens and a code lens resolve request.
	 */
	data?: any
}
  • partial result: CodeLens[]
  • error: code and message set in case an exception happens during the code lens request.

Code Lens Resolve Request (:leftwards_arrow_with_hook:)

The code lens resolve request is sent from the client to the server to resolve the command for a given code lens item.

Request:

  • method: ‘codeLens/resolve’
  • params: CodeLens

Response:

  • result: CodeLens
  • error: code and message set in case an exception happens during the code lens resolve request.

The document links request is sent from the client to the server to request the location of links in a document.

Client Capability:

  • property name (optional): textDocument.documentLink
  • property type: DocumentLinkClientCapabilities defined as follows:
export interface DocumentLinkClientCapabilities {
	/**
	 * Whether document link supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * Whether the client support the `tooltip` property on `DocumentLink`.
	 *
	 * @since 3.15.0
	 */
	tooltipSupport?: boolean;
}

Server Capability:

  • property name (optional): documentLinkProvider
  • property type: DocumentLinkOptions defined as follows:
export interface DocumentLinkOptions extends WorkDoneProgressOptions {
	/**
	 * Document links have a resolve provider as well.
	 */
	resolveProvider?: boolean;
}```

_Registration Options_: `DocumentLinkRegistrationOptions` defined as follows:
```typescript
export interface DocumentLinkRegistrationOptions extends TextDocumentRegistrationOptions, DocumentLinkOptions {
}

Request:

  • method: ‘textDocument/documentLink’
  • params: DocumentLinkParams defined as follows:
interface DocumentLinkParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The document to provide document links for.
	 */
	textDocument: TextDocumentIdentifier;
}

Response:

  • result: DocumentLink[] | null.
/**
 * A document link is a range in a text document that links to an internal or external resource, like another
 * text document or a web site.
 */
interface DocumentLink {
	/**
	 * The range this link applies to.
	 */
	range: Range;

	/**
	 * The uri this link points to. If missing a resolve request is sent later.
	 */
	target?: DocumentUri;

	/**
	 * The tooltip text when you hover over this link.
	 *
	 * If a tooltip is provided, is will be displayed in a string that includes instructions on how to
	 * trigger the link, such as `{0} (ctrl + click)`. The specific instructions vary depending on OS,
	 * user settings, and localization.
	 *
	 * @since 3.15.0
	 */
	tooltip?: string;

	/**
	 * A data entry field that is preserved on a document link between a
	 * DocumentLinkRequest and a DocumentLinkResolveRequest.
	 */
	data?: any;
}
  • partial result: DocumentLink[]
  • error: code and message set in case an exception happens during the document link request.

The document link resolve request is sent from the client to the server to resolve the target of a given document link.

Request:

  • method: ‘documentLink/resolve’
  • params: DocumentLink

Response:

  • result: DocumentLink
  • error: code and message set in case an exception happens during the document link resolve request.

Document Color Request (:leftwards_arrow_with_hook:)

Since version 3.6.0

The document color request is sent from the client to the server to list all color references found in a given text document. Along with the range, a color value in RGB is returned.

Clients can use the result to decorate color references in an editor. For example:

  • Color boxes showing the actual color next to the reference
  • Show a color picker when a color reference is edited

Client Capability:

  • property name (optional): textDocument.colorProvider
  • property type: DocumentColorClientCapabilities defined as follows:
export interface DocumentColorClientCapabilities {
	/**
	 * Whether code lens supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): colorProvider
  • property type: boolean | DocumentColorOptions | DocumentColorRegistrationOptions were DocumentColorOptions is defined as follows:
export interface DocumentColorOptions extends WorkDoneProgressOptions {
	/**
	 * Code lens has a resolve provider as well.
	 */
	resolveProvider?: boolean;
}

Registration Options: DocumentColorRegistrationOptions defined as follows:

export interface DocumentColorRegistrationOptions extends TextDocumentRegistrationOptions, StaticRegistrationOptions, DocumentColorOptions {
}

Request:

  • method: ‘textDocument/documentColor’
  • params: DocumentColorParams defined as follows
interface DocumentColorParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;
}

Response:

  • result: ColorInformation[] defined as follows:
interface ColorInformation {
	/**
	 * The range in the document where this color appears.
	 */
	range: Range;

	/**
	 * The actual color value for this color range.
	 */
	color: Color;
}

/**
 * Represents a color in RGBA space.
 */
interface Color {

	/**
	 * The red component of this color in the range [0-1].
	 */
	readonly red: number;

	/**
	 * The green component of this color in the range [0-1].
	 */
	readonly green: number;

	/**
	 * The blue component of this color in the range [0-1].
	 */
	readonly blue: number;

	/**
	 * The alpha component of this color in the range [0-1].
	 */
	readonly alpha: number;
}
  • partial result: ColorInformation[]
  • error: code and message set in case an exception happens during the ‘textDocument/documentColor’ request

Color Presentation Request (:leftwards_arrow_with_hook:)

Since version 3.6.0

The color presentation request is sent from the client to the server to obtain a list of presentations for a color value at a given location. Clients can use the result to

  • modify a color reference.
  • show in a color picker and let users pick one of the presentations

Request:

  • method: ‘textDocument/colorPresentation’
  • params: ColorPresentationParams defined as follows
interface ColorPresentationParams {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The color information to request presentations for.
	 */
	color: Color;

	/**
	 * The range where the color would be inserted. Serves as a context.
	 */
	range: Range;
}

Response:

  • result: ColorPresentation[] defined as follows:
interface ColorPresentation {
	/**
	 * The label of this color presentation. It will be shown on the color
	 * picker header. By default this is also the text that is inserted when selecting
	 * this color presentation.
	 */
	label: string;
	/**
	 * An [edit](#TextEdit) which is applied to a document when selecting
	 * this presentation for the color.  When `falsy` the [label](#ColorPresentation.label)
	 * is used.
	 */
	textEdit?: TextEdit;
	/**
	 * An optional array of additional [text edits](#TextEdit) that are applied when
	 * selecting this color presentation. Edits must not overlap with the main [edit](#ColorPresentation.textEdit) nor with themselves.
	 */
	additionalTextEdits?: TextEdit[];
}
  • error: code and message set in case an exception happens during the ‘textDocument/colorPresentation’ request

Document Formatting Request (:leftwards_arrow_with_hook:)

The document formatting request is sent from the client to the server to format a whole document.

Client Capability:

  • property name (optional): textDocument.formatting
  • property type: DocumentFormattingClientCapabilities defined as follows:
export interface DocumentFormattingClientCapabilities {
	/**
	 * Whether formatting supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): documentFormattingProvider
  • property type: boolean | DocumentFormattingOptions were DocumentFormattingOptions is defined as follows:
export interface DocumentFormattingOptions extends WorkDoneProgressOptions {
}

Registration Options: DocumentFormattingRegistrationOptions defined as follows:

export interface DocumentFormattingRegistrationOptions extends TextDocumentRegistrationOptions, DocumentFormattingOptions {
}

Request:

  • method: ‘textDocument/formatting’
  • params: DocumentFormattingParams defined as follows
interface DocumentFormattingParams extends WorkDoneProgressParams {
	/**
	 * The document to format.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The format options.
	 */
	options: FormattingOptions;
}

/**
 * Value-object describing what options formatting should use.
 */
interface FormattingOptions {
	/**
	 * Size of a tab in spaces.
	 */
	tabSize: number;

	/**
	 * Prefer spaces over tabs.
	 */
	insertSpaces: boolean;

	/**
	 * Trim trailing whitespaces on a line.
	 *
	 * @since 3.15.0
	 */
	trimTrailingWhitespace?: boolean;

	/**
	 * Insert a newline character at the end of the file if one does not exist.
	 *
	 * @since 3.15.0
	 */
	insertFinalNewline?: boolean;

	/**
	 * Trim all newlines after the final newline at the end of the file.
	 *
	 * @since 3.15.0
	 */
	trimFinalNewlines?: boolean;

	/**
	 * Signature for further properties.
	 */
	[key: string]: boolean | number | string;
}

Response:

  • result: TextEdit[] | null describing the modification to the document to be formatted.
  • error: code and message set in case an exception happens during the formatting request.

Document Range Formatting Request (:leftwards_arrow_with_hook:)

The document range formatting request is sent from the client to the server to format a given range in a document.

Client Capability:

  • property name (optional): textDocument.rangeFormatting
  • property type: DocumentRangeFormattingClientCapabilities defined as follows:
export interface DocumentRangeFormattingClientCapabilities {
	/**
	 * Whether formatting supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): documentRangeFormattingProvider
  • property type: boolean | DocumentRangeFormattingOptions were DocumentRangeFormattingOptions is defined as follows:
export interface DocumentRangeFormattingOptions extends WorkDoneProgressOptions {
}

Registration Options: DocumentFormattingRegistrationOptions defined as follows:

export interface DocumentRangeFormattingRegistrationOptions extends TextDocumentRegistrationOptions, DocumentRangeFormattingOptions {
}

Request:

  • method: ‘textDocument/rangeFormatting’,
  • params: DocumentRangeFormattingParams defined as follows:
interface DocumentRangeFormattingParams extends WorkDoneProgressParams {
	/**
	 * The document to format.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The range to format
	 */
	range: Range;

	/**
	 * The format options
	 */
	options: FormattingOptions;
}

Response:

  • result: TextEdit[] | null describing the modification to the document to be formatted.
  • error: code and message set in case an exception happens during the range formatting request.

Document on Type Formatting Request (:leftwards_arrow_with_hook:)

The document on type formatting request is sent from the client to the server to format parts of the document during typing.

Client Capability:

  • property name (optional): textDocument.onTypeFormatting
  • property type: DocumentOnTypeFormattingClientCapabilities defined as follows:
export interface DocumentOnTypeFormattingClientCapabilities {
	/**
	 * Whether on type formatting supports dynamic registration.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): documentOnTypeFormattingProvider
  • property type: DocumentOnTypeFormattingOptions defined as follows:
export interface DocumentOnTypeFormattingOptions {
	/**
	 * A character on which formatting should be triggered, like `}`.
	 */
	firstTriggerCharacter: string;

	/**
	 * More trigger characters.
	 */
	moreTriggerCharacter?: string[];
}

Registration Options: DocumentOnTypeFormattingRegistrationOptions defined as follows:

export interface DocumentOnTypeFormattingRegistrationOptions extends TextDocumentRegistrationOptions, DocumentOnTypeFormattingOptions {
}

Request:

  • method: ‘textDocument/onTypeFormatting’
  • params: DocumentOnTypeFormattingParams defined as follows:
interface DocumentOnTypeFormattingParams {
	/**
	 * The document to format.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The position at which this request was sent.
	 */
	position: Position;

	/**
	 * The character that has been typed.
	 */
	ch: string;

	/**
	 * The format options.
	 */
	options: FormattingOptions;
}

Response:

  • result: TextEdit[] | null describing the modification to the document.
  • error: code and message set in case an exception happens during the range formatting request.

Rename Request (:leftwards_arrow_with_hook:)

The rename request is sent from the client to the server to perform a workspace-wide rename of a symbol.

Client Capability:

  • property name (optional): textDocument.rename
  • property type: RenameClientCapabilities defined as follows:
export interface RenameClientCapabilities {
	/**
	 * Whether rename supports dynamic registration.
	 */
	dynamicRegistration?: boolean;

	/**
	 * Client supports testing for validity of rename operations
	 * before execution.
	 *
	 * @since version 3.12.0
	 */
	prepareSupport?: boolean;
}

Server Capability:

  • property name (optional): renameProvider
  • property type: boolean | RenameOptions were RenameOptions is defined as follows:

RenameOptions may only be specified if the client states that it supports prepareSupport in its initial initialize request.

export interface RenameOptions extends WorkDoneProgressOptions {
	/**
	 * Renames should be checked and tested before being executed.
	 */
	prepareProvider?: boolean;
}

Registration Options: RenameRegistrationOptions defined as follows:

export interface RenameRegistrationOptions extends TextDocumentRegistrationOptions, RenameOptions {
}

Request:

  • method: ‘textDocument/rename’
  • params: RenameParams defined as follows
interface RenameParams extends WorkDoneProgressParams {
	/**
	 * The document to rename.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The position at which this request was sent.
	 */
	position: Position;

	/**
	 * The new name of the symbol. If the given name is not valid the
	 * request must return a [ResponseError](#ResponseError) with an
	 * appropriate message set.
	 */
	newName: string;
}

Response:

  • result: WorkspaceEdit | null describing the modification to the workspace.
  • error: code and message set in case an exception happens during the rename request.

Prepare Rename Request (:leftwards_arrow_with_hook:)

Since version 3.12.0

The prepare rename request is sent from the client to the server to setup and test the validity of a rename operation at a given location.

Request:

Response:

  • result: Range | { range: Range, placeholder: string } | null describing the range of the string to rename and optionally a placeholder text of the string content to be renamed. If null is returned then it is deemed that a ‘textDocument/rename’ request is not valid at the given position.
  • error: code and message set in case the element can’t be renamed. Clients should show the information in their user interface.

Folding Range Request (:leftwards_arrow_with_hook:)

Since version 3.10.0

The folding range request is sent from the client to the server to return all folding ranges found in a given text document.

Client Capability:

  • property name (optional): textDocument.foldingRange
  • property type: FoldingRangeClientCapabilities defined as follows:
export interface FoldingRangeClientCapabilities {
	/**
	 * Whether implementation supports dynamic registration for folding range providers. If this is set to `true`
	 * the client supports the new `FoldingRangeRegistrationOptions` return value for the corresponding server
	 * capability as well.
	 */
	dynamicRegistration?: boolean;
	/**
	 * The maximum number of folding ranges that the client prefers to receive per document. The value serves as a
	 * hint, servers are free to follow the limit.
	 */
	rangeLimit?: number;
	/**
	 * If set, the client signals that it only supports folding complete lines. If set, client will
	 * ignore specified `startCharacter` and `endCharacter` properties in a FoldingRange.
	 */
	lineFoldingOnly?: boolean;
}

Server Capability:

  • property name (optional): foldingRangeProvider
  • property type: boolean | FoldingRangeOptions | FoldingRangeRegistrationOptions were FoldingRangeOptions is defined as follows:
export interface FoldingRangeOptions extends WorkDoneProgressOptions {
}

Registration Options: FoldingRangeRegistrationOptions defined as follows:

export interface FoldingRangeRegistrationOptions extends TextDocumentRegistrationOptions, FoldingRangeOptions, StaticRegistrationOptions {
}

Request:

  • method: ‘textDocument/foldingRange’
  • params: FoldingRangeParams defined as follows
export interface FoldingRangeParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;
}

Response:

  • result: FoldingRange[] | null defined as follows:
/**
 * Enum of known range kinds
 */
export enum FoldingRangeKind {
	/**
	 * Folding range for a comment
	 */
	Comment = 'comment',
	/**
	 * Folding range for a imports or includes
	 */
	Imports = 'imports',
	/**
	 * Folding range for a region (e.g. `#region`)
	 */
	Region = 'region'
}

/**
 * Represents a folding range.
 */
export interface FoldingRange {

	/**
	 * The zero-based line number from where the folded range starts.
	 */
	startLine: number;

	/**
	 * The zero-based character offset from where the folded range starts. If not defined, defaults to the length of the start line.
	 */
	startCharacter?: number;

	/**
	 * The zero-based line number where the folded range ends.
	 */
	endLine: number;

	/**
	 * The zero-based character offset before the folded range ends. If not defined, defaults to the length of the end line.
	 */
	endCharacter?: number;

	/**
	 * Describes the kind of the folding range such as `comment' or 'region'. The kind
	 * is used to categorize folding ranges and used by commands like 'Fold all comments'. See
	 * [FoldingRangeKind](#FoldingRangeKind) for an enumeration of standardized kinds.
	 */
	kind?: string;
}
  • partial result: FoldingRange[]
  • error: code and message set in case an exception happens during the ‘textDocument/foldingRange’ request

Selection Range Request (:leftwards_arrow_with_hook:)

Since version 3.15.0

The selection range request is sent from the client to the server to return suggested selection ranges at an array of given positions. A selection range is a range around the cursor position which the user might be interested in selecting.

A selection range in the return array is for the position in the provided parameters at the same index. Therefore positions[i] must be contained in result[i].range.

Typically, but not necessary, selection ranges correspond to the nodes of the syntax tree.

Client Capability:

  • property name (optional): textDocument.selectionRange
  • property type: SelectionRangeClientCapabilities defined as follows:
export interface SelectionRangeClientCapabilities {
	/**
	 * Whether implementation supports dynamic registration for selection range providers. If this is set to `true`
	 * the client supports the new `SelectionRangeRegistrationOptions` return value for the corresponding server
	 * capability as well.
	 */
	dynamicRegistration?: boolean;
}

Server Capability:

  • property name (optional): selectionRangeProvider
  • property type: boolean | SelectionRangeOptions | SelectionRangeRegistrationOptions were SelectionRangeOptions is defined as follows:
export interface SelectionRangeOptions extends WorkDoneProgressOptions {
}

Registration Options: SelectionRangeRegistrationOptions defined as follows:

export interface SelectionRangeRegistrationOptions extends SelectionRangeOptions, TextDocumentRegistrationOptions, StaticRegistrationOptions {
}

Request:

  • method: ‘textDocument/selectionRange’
  • params: SelectionRangeParams defined as follows
export interface SelectionRangeParams extends WorkDoneProgressParams, PartialResultParams {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The positions inside the text document.
	 */
	positions: Position[];
}

Response:

  • result: SelectionRange[] | null defined as follows:
export interface SelectionRange {
    /**
     * The [range](#Range) of this selection range.
     */
    range: Range;
    /**
     * The parent selection range containing this range. Therefore `parent.range` must contain `this.range`.
     */
    parent?: SelectionRange;
}
  • partial result: SelectionRange[]
  • error: code and message set in case an exception happens during the ‘textDocument/foldingRange’ request

Implementation considerations

Language servers usually run in a separate process and client communicate with them in an asynchronous fashion. Additionally clients usually allow users to interact with the source code even if request results are pending. We recommend the following implementation pattern to avoid that clients apply outdated response results:

  • if a client sends a request to the server and the client state changes in a way that the result will be invalid it should cancel the server request and ignore the result. If necessary it can resend the request to receive an up to date result.
  • if a server detects a state change that invalidates the result of a request in execution the server can error these requests with ContentModified. If clients receive a ContentModified error, it generally should not show it in the UI for the end-user. Clients can resend the request if appropriate.
  • if servers end up in an inconsistent state they should log this to the client using the window/logMessage request. If they can’t recover from this the best they can do right now is to exit themselves. We are considering an extension to the protocol that allows servers to request a restart on the client side.
  • if a client notices that a server exits unexpectedly, it should try to restart the server. However clients should be careful not to restart a crashing server endlessly. VS Code, for example, doesn’t restart a server which has crashed 5 times in the last 180 seconds.

Change Log

3.15.0 (09/19/2019)

  • Add generic progress reporting support.
  • Add specific work done progress reporting support to requests were applicable.
  • Add specific partial result progress support to requests were applicable.
  • Add support for textDocument/selectionRange.
  • Add support for server and client information.
  • Add signature help context.
  • Add Erlang and Elixir to the list of supported programming languages
  • Add version on PublishDiagnosticsParams
  • Add CodeAction#isPreferred support.
  • Add CompletionItem#tag support.
  • Add Diagnostic#tag support.
  • Add DocumentLink#tooltip support.
  • Add trimTrailingWhitespace, insertFinalNewline and trimFinalNewlines to FormattingOptions.
  • Clarified WorkspaceSymbolParams#query parameter.

3.14.0 (12/13/2018)

  • Add support for signature label offsets.
  • Add support for location links.
  • Add support for textDocument/declaration request.

3.13.0 (9/11/2018)

  • Add support for file and folder operations (create, rename, move) to workspace edits.

3.12.0 (8/23/2018)

  • Add support for textDocument/prepareRename request.

3.11.0 (8/21/2018)

  • Add support for CodeActionOptions to allow a server to provide a list of code action it supports.

3.10.0 (7/23/2018)

  • Add support for hierarchical document symbols as a valid response to a textDocument/documentSymbol request.
  • Add support for folding ranges as a valid response to a textDocument/foldingRange request.

3.9.0 (7/10/2018)

  • Add support for preselect property in CompletionItem

3.8.0 (6/11/2018)

  • Added support for CodeAction literals to the textDocument/codeAction request.
  • ColorServerCapabilities.colorProvider can also be a boolean
  • Corrected ColorPresentationParams.colorInfo to color (as in the d.ts and in implementations)

3.7.0 (4/5/2018)

  • Added support for related information to Diagnostics.

3.6.0 (2/22/2018)

Merge the proposed protocol for workspace folders, configuration, go to type definition, go to implementation and document color provider into the main branch of the specification. For details see:

In addition we enhanced the CompletionTriggerKind with a new value TriggerForIncompleteCompletions: 3 = 3 to signal the a completion request got trigger since the last result was incomplete.

3.5.0

Decided to skip this version to bring the protocol version number in sync the with npm module vscode-languageserver-protocol.

3.4.0 (11/27/2017)

3.3.0 (11/24/2017)

  • Added support for CompletionContext
  • Added support for MarkupContent
  • Removed old New and Updated markers.

3.2.0 (09/26/2017)

  • Added optional commitCharacters property to the CompletionItem

3.1.0 (02/28/2017)

  • Make the WorkspaceEdit changes backwards compatible.
  • Updated the specification to correctly describe the breaking changes from 2.x to 3.x around WorkspaceEditand TextDocumentEdit.

3.0 Version

  • add support for client feature flags to support that servers can adapt to different client capabilities. An example is the new textDocument/willSaveWaitUntil request which not all clients might be able to support. If the feature is disabled in the client capabilities sent on the initialize request, the server can’t rely on receiving the request.
  • add support to experiment with new features. The new ClientCapabilities.experimental section together with feature flags allow servers to provide experimental feature without the need of ALL clients to adopt them immediately.
  • servers can more dynamically react to client features. Capabilities can now be registered and unregistered after the initialize request using the new client/registerCapability and client/unregisterCapability. This for example allows servers to react to settings or configuration changes without a restart.
  • add support for textDocument/willSave notification and textDocument/willSaveWaitUntil request.
  • add support for textDocument/documentLink request.
  • add a rootUri property to the initializeParams in favor of the rootPath property.