action-emitter

Action emitter based on fbemitter. Instead of string event types we use classes (functions). The package is most useful when used with TypeScript.

Get started

$ npm install action-emitter --save-dev

Usage

First import the action-emitter package and then create a new emitter instance.

import { ActionEmitter } from "action-emitter";
const Emitter = new ActionEmitter();

API

constructor(): void

Create a new emitter instance.

Emitter construction example:

const Emitter = new ActionEmitter();

addListener(actionClass, callback): EventSubscription

Register a specific callback to be called on a particular action event. A subscription is returned that can be called to remove the listener.

Arguments

| Argument | Type | Description | |---------------|-----------------------------|-----------------------------| | actionClass | Function | Action class function. | | callback | (action: TAction) => void | Listener callback function. |

Add listener example:

class MyAction {
    constructor(private value: string) { }
    public get Value() {
        return this.value;
    }
}

let subsciption = Emitter.addListener<MyAction>(MyAction, action => {
    console.log(action.Value);
});

once(actionClass, callback): EventSubscription

Similar to addListener() but the callback is removed after it is invoked once. A subscription is returned that can be called to remove the listener.

Arguments

| Argument | Type | Description | |---------------|-----------------------------|-----------------------------| | actionClass | Function | Action class function. | | callback | (action: TAction) => void | Listener callback function. |

Add once listener example:

class MyAction {
    constructor(private value: string) { }
    public get Value() {
        return this.value;
    }
}

let subsciption = Emitter.once<MyAction>(MyAction, action => {
    console.log(action.Value);
});

removeAllListeners(actionClass): void

Removes all of the registered listeners. If provide actionClass, only listeners for that action class are removed.

Arguments

| Argument | Type | Description | |-----------------------------|-------------|-----------------------------| | actionClass[*] | Function | Action class function. |

[*] - optional.

Remove all listeners example:

class MyAction {
    constructor(private value: string) { }
    public get Value() {
        return this.value;
    }
}

Emitter.removeAllListeners(MyAction);
// Or
Emitter.removeAllListeners();

listeners(actionClass): Function[]

Returns an array of listeners that are currently registered for the given action class.

Arguments

| Argument | Type | Description | |---------------|------------|-----------------------------| | actionClass | Function | Action class function. |

Listeners list example:

let listenersList = Emitter.listeners();

listenersCount(actionClass): number

Return listeners count that are currently registered for the given action class. If action class is not specified, method will return all registered action listeners count.

Arguments

| Argument | Type | Description | |-----------------------------|------------|-----------------------------| | actionClass[*] | Function | Action class function. |

[*] - optional.

Listeners list example:

class MyAction {
    constructor(private value: string) { }
    public get Value() {
        return this.value;
    }
}

let globalListenersCount = Emitter.listenersCount();
// or 
let listenersCount = Emitter.listenersCount(MyAction);

emit(action): void

Emits an action event with the given data. All callbacks that are listening to the particular action event will be notified.

Arguments

| Argument | Type | Description | |---------------|-----------|-----------------------------| | action | TAction | Action class instance. |

Action emit example:

class MyAction {
    constructor(private value: string) { }
    public get Value() {
        return this.value;
    }
}

Emitter.emit<MyAction>(new MyAction("value"));
//or 
Emitter.emit(new MyAction("value"));

Debuging

You can listen to all actions with AnyAction class.

import { AnyAction } from "action-emitter";
Emitter.addListener(AnyAction, anyAction => {
    let actionInstance = anyAction.Action;
    console.log(actionInstance);
});

License

Released under the MIT license.