bdwenxi / bd-emitter

A lightweight event emitter implementation base on typescript.

bd-emitter

A lightweight event emitter implementation base on typescript.

Getting Started

Install

Install the bd-emitter package via npm:

npm install bd-emitter

Install the bd-emitter package via yarn:

yarn add bd-emitter

Import or Require

import EventEmitter from 'bd-emitter';

const EventEmitter = require('bd-emitter');

Usage

import EventEmitter from 'bd-emitter';

const emitter = new EventEmitter();

emitter.on('search', function (...args) {
    console.log(args);
});

setTimeout(
    function () {
        emitter.emit('search', 'Baidu');
    },
    1000
);

API

on(eventName: string, callback: Function, context: Object)

Register a specific callback to be called on a custom event.

import EventEmitter from 'bd-emitter';

const emitter = new EventEmitter();

const callback = function (...args) {
    console.log(...args);
};

emitter.on('search', callback);
emitter.emit('search', 'Baidu AI'); // Baidu AI

once(eventName: string, callback: Function, context: Object)

Similar to on() but the callback is removed after it is invoked once.

import EventEmitter from 'bd-emitter';

const emitter = new EventEmitter();

const callback = function (...args) {
    console.log(...args);
};

emitter.once('search', callback);
emitter.emit('search', 'Baidu AI'); // Baidu AI
emitter.emit('search', 'Baidu AI'); // nothing

off(eventName?: string, listener?: Function)

eventName is optional, if provided only listeners for that event name are removed, otherwise remove all events.

import EventEmitter from 'bd-emitter';

const emitter = new EventEmitter();

const callback = function (...args) {
    console.log(...args);
};

emitter.on('search', callback);
emitter.emit('search', 'Baidu AI'); // Baidu AI
emitter.off('search', callback);
emitter.emit('search', 'Baidu AI'); // nothing

import EventEmitter from 'bd-emitter';

const emitter = new EventEmitter();

const callback1 = function (...args) {
    console.log(...args);
};

const callback2 = function (...args) {
    console.log(...args);
};

emitter.on('custom:search', callback1);
emitter.on('custom:navigation', callback2);
emitter.emit('custom:search', 'Baidu Search'); // Baidu Search
emitter.emit('custom:navigation', 'Baidu Navigation'); // Baidu Navigation

emitter.off();

emitter.emit('custom:search', 'Baidu Search'); // nothing
emitter.emit('custom:navigation', 'Baidu Navigation'); // nothing

emit(eventName: string, ...args: any[])

Emits an event of the given type with the given data.

import EventEmitter from 'bd-emitter';

const emitter = new EventEmitter();

const callback = function (...args) {
    console.log(...args);
};

emitter.on('search', callback);
emitter.emit('search', 'Baidu AI'); // Baidu AI

Running the tests

git clone [email protected]:bdwenxi/bd-emitter.git

yarn

jest

Contributing

bdwenxi ([email protected])

Authors

bdwenxi ([email protected])

License

This project is licensed under the MIT License