dual-emitter

    0.7.0 • Public • Published

    dual-emitter npmjs.com The MIT License

    EventEmitter done right and no dependencies. For nodejs and the browser (>= IE8). Can emit custom or DOM events.

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    Install

    npm i dual-emitter --save
    npm test
    

    Features

    • minimal, yet simple to use
    • just 4kb minified - no jQuery, no dependencies
    • works on the browser (even IE8), use dist/dual-emitter.min.js
    • works on the server, just install it and require it
    • can emit (trigger or whatever you call it) DOM events manually
    • have .on, .off, .once and .emit methods

    Usage

    For more use-cases see the tests

    var DualEmitter = require('dual-emitter')
    var emitter = new DualEmitter()
     
    function handler () {
      console.log('foo bar')
    }
     
    emitter
      .once('custom', function () {
        console.log('executed once')
      })
      .on('foo', handler)
      .emit('custom', 'abc')
      .emit('custom', 'foo', ['bar', 'baz'])
      .emit('custom')
      .off('foo', handler)
      .on('click', function () {
        console.log('link clicked')
      }, document.body.querySelector('a[href]'))

    API

    DualEmitter

    Create a new instance of DualEmitter.

    • [events] {Object} Initialize with default events.

    Example

    var DualEmitter = require('dual-emitter')
    var emitter = new DualEmitter()

    .on

    Add/bind event listener to custom or DOM event. Notice that this in event handler function vary - it can be the DOM element or DualEmitter instance.

    • <name> {String} event name
    • <fn> {Function} event handler
    • [el] {Object} optional DOM element
    • returns {DualEmitter} DualEmitter for chaining

    Example

    function handler (a, b) {
      console.log('hi', a, b) //=> hi 123 bar
    }
     
    function onclick (evt) {
      console.log(evt, 'clicked')
    }
     
    var element = document.body.querySelector('a.link')
     
    emitter.on('custom', handler).emit('custom', 123, 'bar')
    emitter.on('click', onclick, element).off('click', onclick, element)

    .off

    Remove/unbind event listener of custom or DOM event.

    • <name> {String} event name
    • <fn> {Function} event handler
    • [el] {Object} optional DOM element
    • returns {DualEmitter} DualEmitter for chaining

    Example

    var element = document.body.querySelector('a.link')
    emitter.off('custom', handler)
    emitter.off('click', onclick, element)

    .once

    Add one-time event listener to custom or DOM event. Notice that this in event handler function vary - it can be the DOM element or DualEmitter instance.

    • <name> {String} event name
    • <fn> {Function} event handler
    • [el] {Object} optional DOM element
    • returns {DualEmitter} DualEmitter for chaining

    Example

    emitter
      .once('custom', function () {
        console.log('executed one time')
      })
      .emit('custom')
      .emit('custom')
     
    var element = document.body.querySelector('a.link')
    emitter.once('click', function () {
      console.log('listen for click event only once')
    }, element)

    .emit

    Emit/execute some type of event listener. You also can emit DOM events if last argument is the DOM element that have attached event listener.

    • <name> {String} event name
    • [args...] {Mixed} context to pass to event listeners
    • [el] {Object} optional DOM element
    • returns {DualEmitter} DualEmitter for chaining

    Example

    var i = 0
     
    emitter
      .on('custom', function () {
        console.log('i ==', i++, arguments)
      })
      .emit('custom')
      .emit('custom', 123)
      .emit('custom', 'foo', 'bar', 'baz')
      .emit('custom', [1, 2, 3], 4, 5)
     
    // or even emit DOM events, but you should
    // give the element as last argument to `.emit` method
    var element = document.body.querySelector('a.link')
    var clicks = 0
     
    emitter
      .on('click', function (a) {
        console.log(a, 'clicked', clicks++)
      }, element)
      .emit('click', 123, element)
      .emit('click', element)
      .emit('click', foo, element)

    ._isDom

    Check that given val is DOM element. Used internally.

    • val {Mixed}
    • returns {Boolean}

    Example

    var element = document.body.querySelector('a.link')
     
    emitter._isDom(element) //=> true
    emitter._isDom({a: 'b'}) //=> false

    ._hasOwn

    Check that key exists in the given obj.

    • obj {Object}
    • key {String}
    • returns {Boolean}

    Example

    var obj = {a: 'b'}
     
    emitter._hasOwn(obj, 'a') //=> true
    emitter._hasOwn(obj, 'foo') //=> false

    .extend

    Static method for inheriting both the prototype and static methods of the DualEmitter class.

    • Ctor {Function} The constructor to extend.

    Example

    function MyApp(options) {
      DualEmitter.call(this)
    }
    DualEmitter.extend(MyApp)
     
    // Optionally pass another object to extend onto `MyApp`
    function MyApp(options) {
      DualEmitter.call(this)
      Foo.call(this, options)
    }
    DualEmitter.extend(MyApp, Foo.prototype)

    Contributing

    Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
    But before doing anything, please read the CONTRIBUTING.md guidelines.

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    Install

    npm i dual-emitter

    DownloadsWeekly Downloads

    12

    Version

    0.7.0

    License

    MIT

    Last publish

    Collaborators

    • vanchoy
    • tunnckocore