mutator

Registers a function as a mutator.

Usage

mutator(actionCreator, target)

Arguments

• actionCreator (ActionCreator): The action creator of the action to subscribe to.
• target ((ActionMessage) => void): The function to register as a mutator.

Return value

• ((ActionMessage) => void): The target function.

Example

let addTodo = actionCreator(
    'ADD_TODO',
    (text: string) => ({ text: text }));

mutator(addTodo, (actionMessage) => {
    getStore().todos.push({
        id: Math.random(),
        text: actionMessage.text
    });
});

Notes

• The target function gets called whenever an action of the subscribed type is dispatched.
• Mutators are responsible for modifying the store in response to actions. They should not dispatch other actions or have any other side effects.
• Note that a mutator is registered to an action by passing that action's action creator as the first argument. This is a little unusual, but convenient because it allows TypeScript to infer the type of the action message.
• For convenience, mutator returns target. While you don't need to export a mutator function, it may be convenient to do so for testing purposes.