jfusco / es6-event-emitter

Custom, simple, extendable event/messaging system written in ES6

es6-event-emitter

Custom, simple, extendable event/messaging system written in ES6

Getting Started

Installation

From the root of your project.

npm install es6-event-emitter --save

Usage

Simple implementation of emitter. See api below.

import Emitter from 'es6-event-emitter';

export default class Component extends Emitter {
	constructor(){
		super();
	}

	//-- Trigger
	someAction(){
		...

		this.trigger('component:action');
	}

	//-- Trigger with data
	someOtherAction(){
		...

        this.trigger('component:otheraction', {
            foo: 'bar',
            baz: 'buzz'
        });
    }
}

//-- Create a new component
const component = new Component();

//-- Set up functions for listeners - best practice in case you want to remove them later.
const action = () => {
	console.log('action triggered');
}

const otheraction = data => {
	console.log(`other action triggered with data ${data}`);
}

//-- Register listeners
component.on('component:action', action);
component.on('component:otheraction', otheraction);

//-- Call methods
component.someAction();
component.someOtherAction();

API

• on
• off
• once
• trigger
• destroy

on - on(event:String, callback:Function)

Registers a listener

component.on('component:action', action);

off - off(event:String, callback:Function)

Removes a registered listener from the event stack

component.off('component:action', action);

once - once(event:String, callback:Function)

Registers a listener that will only fire once no matter how many times you try to trigger

component.once('component:action', action);

trigger - trigger(event:String, ...args:*)

Triggers a registered event with optional data

this.trigger('component:action');

//-- With data
this.trigger('component:action', {
    foo: 'bar',
    baz: 'buzz'
});

destroy - destroy()

Destroys the entire event emitter

component.destroy();

Tests

View the test coverage

npm test

es6-event-emitter's Issues

why the restriction on node version?

Do you have a specific reason to lock your package to >=7.7.0 <=8.1.x?

TIA

Dependency on babel-runtime

Attempting to use es6-event-emitter without babel-runtime as a direct dependency results in this error:

module.js:327
    throw err;
    ^

Error: Cannot find module 'babel-runtime/helpers/classCallCheck'
    at Function.Module._resolveFilename (module.js:325:15)
    at Function.Module._load (module.js:276:25)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
    at Object.<anonymous> (/Users/pwagener/Devel/callbacks/node_modules/es6-event-emitter/dist/emitter.js:7:24)
    at Module._compile (module.js:409:26)
    at Module._extensions..js (module.js:416:10)
    at Object.require.extensions.(anonymous function) [as .js] (/Users/pwagener/Devel/callbacks/node_modules/babel-register/lib/node.js:154:7)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
   ...

Adding babel-runtime as a direct dependency of my project seems to resolve it.

Cannot find module 'babel-runtime/helpers/classCallCheck'

Hi there, your class looks promising! I am having problems, while trying it out: The compiler says this:

Error: Cannot find module 'babel-runtime/helpers/classCallCheck' from 'node_modules/es6-event-emitter/dist'

Any ideas what I should do about that?

NPM Mismatch distro bundle

The fix for #3 is that the package needs to be updated in NPM. If you look in dist:

var _classCallCheck2 = require('babel-runtime/helpers/classCallCheck');
var _classCallCheck3 = _interopRequireDefault(_classCallCheck2);
var _createClass2 = require('babel-runtime/helpers/createClass');
var _createClass3 = _interopRequireDefault(_createClass2);
var _weakMap = require('babel-runtime/core-js/weak-map');

Triggering events before dom is ready

Hello,

I'm wondering if it's possible to trigger an event on the constructor, or a method that is called immediately after the class is instantiated.

I'm trying to do something like this;

class Bla extends Emitter {
  constructor() {
    super()
    this.trigger('bla:initialised')
}
}

I notice this event doesn't fire, probably because it hasn't fully loaded or something. How would you do something like this?

Cheers

.bablerc in npm package

I'm trying to use this with react-native and ran into it trying to run the .bablerc file from within node_modules. It blows up because of the plugin not being present. Apparently, the convention is becoming not to ship the .bablerc in the npm package by adding it to .npmignore.

facebook/react-native#4062

Are you onboard with that?

add "once" listener

Hi there, would it be possible to also introduce a new "once" listener?