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Module "node:fs/promises"

Index

Interfaces

Functions

Functions

access

  • access(path: PathLike, mode?: number): Promise<void>

  • Asynchronously tests a user's permissions for the file specified by path.

    Parameters

    • path: PathLike

      A path to a file or directory. If a URL is provided, it must use the file: protocol. URL support is experimental.

    • Optional mode: number

    Returns Promise<void>

appendFile

  • Asynchronously append data to a file, creating the file if it does not exist.

    Parameters

    • path: PathLike | FileHandle
    • data: string | Uint8Array

      The data to write. If something other than a Buffer or Uint8Array is provided, the value is coerced to a string.

    • Optional options: BaseEncodingOptions & object | BufferEncoding | null

      Either the encoding for the file, or an object optionally specifying the encoding, file mode, and flag. If encoding is not supplied, the default of 'utf8' is used. If mode is not supplied, the default of 0o666 is used. If mode is a string, it is parsed as an octal integer. If flag is not supplied, the default of 'a' is used.

    Returns Promise<void>

chmod

  • Asynchronous chmod(2) - Change permissions of a file.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • mode: Mode

      A file mode. If a string is passed, it is parsed as an octal integer.

    Returns Promise<void>

chown

  • chown(path: PathLike, uid: number, gid: number): Promise<void>

  • Asynchronous chown(2) - Change ownership of a file.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • uid: number
    • gid: number

    Returns Promise<void>

copyFile

  • Asynchronously copies src to dest. By default, dest is overwritten if it already exists. Node.js makes no guarantees about the atomicity of the copy operation. If an error occurs after the destination file has been opened for writing, Node.js will attempt to remove the destination.

    Parameters

    • src: PathLike

      A path to the source file.

    • dest: PathLike

      A path to the destination file.

    • Optional flags: number

      An optional integer that specifies the behavior of the copy operation. The only supported flag is fs.constants.COPYFILE_EXCL, which causes the copy operation to fail if dest already exists.

    Returns Promise<void>

fchmod

  • Asynchronous fchmod(2) - Change permissions of a file.

    Parameters

    • handle: FileHandle

      A FileHandle.

    • mode: Mode

      A file mode. If a string is passed, it is parsed as an octal integer.

    Returns Promise<void>

fchown

  • fchown(handle: FileHandle, uid: number, gid: number): Promise<void>

  • Asynchronous fchown(2) - Change ownership of a file.

    Parameters

    • handle: FileHandle

      A FileHandle.

    • uid: number
    • gid: number

    Returns Promise<void>

fdatasync

  • Asynchronous fdatasync(2) - synchronize a file's in-core state with storage device.

    Parameters

    Returns Promise<void>

fsync

  • Asynchronous fsync(2) - synchronize a file's in-core state with the underlying storage device.

    Parameters

    Returns Promise<void>

ftruncate

  • ftruncate(handle: FileHandle, len?: number): Promise<void>

  • Asynchronous ftruncate(2) - Truncate a file to a specified length.

    Parameters

    • handle: FileHandle

      A FileHandle.

    • Optional len: number

      If not specified, defaults to 0.

    Returns Promise<void>

futimes

  • futimes(handle: FileHandle, atime: string | number | Date, mtime: string | number | Date): Promise<void>

  • Asynchronously change file timestamps of the file referenced by the supplied FileHandle.

    Parameters

    • handle: FileHandle

      A FileHandle.

    • atime: string | number | Date

      The last access time. If a string is provided, it will be coerced to number.

    • mtime: string | number | Date

      The last modified time. If a string is provided, it will be coerced to number.

    Returns Promise<void>

lchmod

  • Asynchronous lchmod(2) - Change permissions of a file. Does not dereference symbolic links.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • mode: Mode

      A file mode. If a string is passed, it is parsed as an octal integer.

    Returns Promise<void>

lchown

  • lchown(path: PathLike, uid: number, gid: number): Promise<void>

  • Asynchronous lchown(2) - Change ownership of a file. Does not dereference symbolic links.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • uid: number
    • gid: number

    Returns Promise<void>

link

  • Asynchronous link(2) - Create a new link (also known as a hard link) to an existing file.

    Parameters

    • existingPath: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • newPath: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    Returns Promise<void>

lstat

  • Asynchronous lstat(2) - Get file status. Does not dereference symbolic links.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional opts: StatOptions & object

    Returns Promise<Stats>

  • Parameters

    Returns Promise<BigIntStats>

  • Parameters

    Returns Promise<Stats | BigIntStats>

lutimes

  • lutimes(path: PathLike, atime: string | number | Date, mtime: string | number | Date): Promise<void>

  • Changes the access and modification times of a file in the same way as fsPromises.utimes(), with the difference that if the path refers to a symbolic link, then the link is not dereferenced: instead, the timestamps of the symbolic link itself are changed.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • atime: string | number | Date

      The last access time. If a string is provided, it will be coerced to number.

    • mtime: string | number | Date

      The last modified time. If a string is provided, it will be coerced to number.

    Returns Promise<void>

mkdir

  • Asynchronous mkdir(2) - create a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • options: MakeDirectoryOptions & object

      Either the file mode, or an object optionally specifying the file mode and whether parent folders should be created. If a string is passed, it is parsed as an octal integer. If not specified, defaults to 0o777.

    Returns Promise<string | undefined>

  • Asynchronous mkdir(2) - create a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: Mode | MakeDirectoryOptions & object | null

      Either the file mode, or an object optionally specifying the file mode and whether parent folders should be created. If a string is passed, it is parsed as an octal integer. If not specified, defaults to 0o777.

    Returns Promise<void>

  • Asynchronous mkdir(2) - create a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: Mode | MakeDirectoryOptions | null

      Either the file mode, or an object optionally specifying the file mode and whether parent folders should be created. If a string is passed, it is parsed as an octal integer. If not specified, defaults to 0o777.

    Returns Promise<string | undefined>

mkdtemp

  • Asynchronously creates a unique temporary directory. Generates six random characters to be appended behind a required prefix to create a unique temporary directory.

    Parameters

    • prefix: string
    • Optional options: BaseEncodingOptions | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string>

  • Asynchronously creates a unique temporary directory. Generates six random characters to be appended behind a required prefix to create a unique temporary directory.

    Parameters

    • prefix: string
    • options: BufferEncodingOption

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<Buffer>

  • Asynchronously creates a unique temporary directory. Generates six random characters to be appended behind a required prefix to create a unique temporary directory.

    Parameters

    • prefix: string
    • Optional options: BaseEncodingOptions | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string | Buffer>

open

  • Asynchronous open(2) - open and possibly create a file.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • flags: string | number
    • Optional mode: Mode

      A file mode. If a string is passed, it is parsed as an octal integer. If not supplied, defaults to 0o666.

    Returns Promise<FileHandle>

opendir

  • Parameters

    Returns Promise<Dir>

read

  • read<TBuffer>(handle: FileHandle, buffer: TBuffer, offset?: number | null, length?: number | null, position?: number | null): Promise<object>

  • Asynchronously reads data from the file referenced by the supplied FileHandle.

    Type parameters

    • TBuffer: Uint8Array

    Parameters

    • handle: FileHandle

      A FileHandle.

    • buffer: TBuffer

      The buffer that the data will be written to.

    • Optional offset: number | null

      The offset in the buffer at which to start writing.

    • Optional length: number | null

      The number of bytes to read.

    • Optional position: number | null

      The offset from the beginning of the file from which data should be read. If null, data will be read from the current position.

    Returns Promise<object>

readFile

  • Asynchronously reads the entire contents of a file.

    Parameters

    • path: PathLike | FileHandle

      A path to a file. If a URL is provided, it must use the file: protocol. If a FileHandle is provided, the underlying file will not be closed automatically.

    • Optional options: object | null

      An object that may contain an optional flag. If a flag is not provided, it defaults to 'r'.

    Returns Promise<Buffer>

  • Asynchronously reads the entire contents of a file.

    Parameters

    • path: PathLike | FileHandle

      A path to a file. If a URL is provided, it must use the file: protocol. If a FileHandle is provided, the underlying file will not be closed automatically.

    • options: object | BufferEncoding

      An object that may contain an optional flag. If a flag is not provided, it defaults to 'r'.

    Returns Promise<string>

  • Asynchronously reads the entire contents of a file.

    Parameters

    • path: PathLike | FileHandle

      A path to a file. If a URL is provided, it must use the file: protocol. If a FileHandle is provided, the underlying file will not be closed automatically.

    • Optional options: BaseEncodingOptions & object | BufferEncoding | null

      An object that may contain an optional flag. If a flag is not provided, it defaults to 'r'.

    Returns Promise<string | Buffer>

readdir

  • Asynchronous readdir(3) - read a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: BaseEncodingOptions & object | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string[]>

  • Asynchronous readdir(3) - read a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • options: object | "buffer"

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<Buffer[]>

  • Asynchronous readdir(3) - read a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: BaseEncodingOptions & object | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string[] | Buffer[]>

  • Asynchronous readdir(3) - read a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • options: BaseEncodingOptions & object

      If called with withFileTypes: true the result data will be an array of Dirent.

    Returns Promise<Dirent[]>

readlink

  • Asynchronous readlink(2) - read value of a symbolic link.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: BaseEncodingOptions | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string>

  • Asynchronous readlink(2) - read value of a symbolic link.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • options: BufferEncodingOption

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<Buffer>

  • Asynchronous readlink(2) - read value of a symbolic link.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: BaseEncodingOptions | string | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string | Buffer>

realpath

  • Asynchronous realpath(3) - return the canonicalized absolute pathname.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: BaseEncodingOptions | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string>

  • Asynchronous realpath(3) - return the canonicalized absolute pathname.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • options: BufferEncodingOption

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<Buffer>

  • Asynchronous realpath(3) - return the canonicalized absolute pathname.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: BaseEncodingOptions | BufferEncoding | null

      The encoding (or an object specifying the encoding), used as the encoding of the result. If not provided, 'utf8' is used.

    Returns Promise<string | Buffer>

rename

  • Asynchronous rename(2) - Change the name or location of a file or directory.

    Parameters

    • oldPath: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol. URL support is experimental.

    • newPath: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol. URL support is experimental.

    Returns Promise<void>

rm

  • Asynchronously removes files and directories (modeled on the standard POSIX rm utility).

    Parameters

    Returns Promise<void>

rmdir

  • Asynchronous rmdir(2) - delete a directory.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional options: RmDirOptions

    Returns Promise<void>

stat

  • Asynchronous stat(2) - Get file status.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional opts: StatOptions & object

    Returns Promise<Stats>

  • Parameters

    Returns Promise<BigIntStats>

  • Parameters

    Returns Promise<Stats | BigIntStats>

symlink

  • symlink(target: PathLike, path: PathLike, type?: string | null): Promise<void>

  • Asynchronous symlink(2) - Create a new symbolic link to an existing file.

    Parameters

    • target: PathLike

      A path to an existing file. If a URL is provided, it must use the file: protocol.

    • path: PathLike

      A path to the new symlink. If a URL is provided, it must use the file: protocol.

    • Optional type: string | null

      May be set to 'dir', 'file', or 'junction' (default is 'file') and is only available on Windows (ignored on other platforms). When using 'junction', the target argument will automatically be normalized to an absolute path.

    Returns Promise<void>

truncate

  • truncate(path: PathLike, len?: number): Promise<void>

  • Asynchronous truncate(2) - Truncate a file to a specified length.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • Optional len: number

      If not specified, defaults to 0.

    Returns Promise<void>

unlink

  • Asynchronous unlink(2) - delete a name and possibly the file it refers to.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    Returns Promise<void>

utimes

  • utimes(path: PathLike, atime: string | number | Date, mtime: string | number | Date): Promise<void>

  • Asynchronously change file timestamps of the file referenced by the supplied path.

    Parameters

    • path: PathLike

      A path to a file. If a URL is provided, it must use the file: protocol.

    • atime: string | number | Date

      The last access time. If a string is provided, it will be coerced to number.

    • mtime: string | number | Date

      The last modified time. If a string is provided, it will be coerced to number.

    Returns Promise<void>

write

  • write<TBuffer>(handle: FileHandle, buffer: TBuffer, offset?: number | null, length?: number | null, position?: number | null): Promise<object>
  • write(handle: FileHandle, string: string, position?: number | null, encoding?: BufferEncoding | null): Promise<object>

  • Asynchronously writes buffer to the file referenced by the supplied FileHandle. It is unsafe to call fsPromises.write() multiple times on the same file without waiting for the Promise to be resolved (or rejected). For this scenario, fs.createWriteStream is strongly recommended.

    Type parameters

    • TBuffer: Uint8Array

    Parameters

    • handle: FileHandle

      A FileHandle.

    • buffer: TBuffer

      The buffer that the data will be written to.

    • Optional offset: number | null

      The part of the buffer to be written. If not supplied, defaults to 0.

    • Optional length: number | null

      The number of bytes to write. If not supplied, defaults to buffer.length - offset.

    • Optional position: number | null

      The offset from the beginning of the file where this data should be written. If not supplied, defaults to the current position.

    Returns Promise<object>

  • Asynchronously writes string to the file referenced by the supplied FileHandle. It is unsafe to call fsPromises.write() multiple times on the same file without waiting for the Promise to be resolved (or rejected). For this scenario, fs.createWriteStream is strongly recommended.

    Parameters

    • handle: FileHandle

      A FileHandle.

    • string: string

      A string to write.

    • Optional position: number | null

      The offset from the beginning of the file where this data should be written. If not supplied, defaults to the current position.

    • Optional encoding: BufferEncoding | null

      The expected string encoding.

    Returns Promise<object>

writeFile

  • Asynchronously writes data to a file, replacing the file if it already exists. It is unsafe to call fsPromises.writeFile() multiple times on the same file without waiting for the Promise to be resolved (or rejected).

    Parameters

    • path: PathLike | FileHandle

      A path to a file. If a URL is provided, it must use the file: protocol. URL support is experimental. If a FileHandle is provided, the underlying file will not be closed automatically.

    • data: string | Uint8Array

      The data to write. If something other than a Buffer or Uint8Array is provided, the value is coerced to a string.

    • Optional options: BaseEncodingOptions & object | BufferEncoding | null

      Either the encoding for the file, or an object optionally specifying the encoding, file mode, and flag. If encoding is not supplied, the default of 'utf8' is used. If mode is not supplied, the default of 0o666 is used. If mode is a string, it is parsed as an octal integer. If flag is not supplied, the default of 'w' is used.

    Returns Promise<void>

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