A Pen by Keili Olsen.

EMES-micro-events.markdown

EMES micro-events

A lightweight event system for rapid prototyping

A Pen by Keili Olsen on CodePen.

License.

emes.js

/**
 *
 * Embarrassingly Minimal Event System
 * Keili Olsen @pentaphobe 2014
 * 
 * CC sharealike
 *
 **/
(function(glob) {
  
  var __ = glob.__ || ( glob.__ = {} );
  var reEvent = /\s+/;
  
  var Eventable = __.Eventable = function() {
    this.listeners = { };
  };
  
  Eventable.prototype.on = function(events, callback) {
    // this would be preferable with lodash/underscore to avoid the _this
    var listeners = this.listeners;
    events.split(reEvent).forEach(function(event, idx) {
      (listeners[event] || (listeners[event] = [])).push(callback);
    });
    return this;
  };
  
  Eventable.prototype.off = function(events, callback) {
    var listeners = this.listeners;
    events.split(reEvent).forEach(function(event, idx) {
      if (!callback) {
        listeners[event] = [];
        return;
      }
      for ( var handlers = listeners[event] || [], idx = 0;
           (idx = handlers.indexOf(callback)) > -1; ) {
        handlers.splice(idx, 1);
      }
      listeners[event] = handlers;
    });
    return this;
  };
  
  Eventable.prototype.trigger = function(events){
    var _this = this;
    var args = Array.prototype.slice.call(arguments, 0);
    events.split(reEvent).forEach(function(event, idx) {
      args[0] = event;
      for ( var handlers = _this.listeners[event], idx = 0, max=handlers.length;
        handlers && idx < max; idx++)
      {
        handlers[idx].apply(_this, args);
      }      
    });
    return this;
  };
  
})(this);

emes.min.js

/** Embarrassingly Minimal Event System, Keili Olsen @pentaphobe 2014, CC sharealike **/
(function(a){var f=/\s+/;a=(a.__||(a.__={})).Eventable=function(){this.listeners={}};a.prototype.on=function(a,c){var b=this.listeners;a.split(f).forEach(function(g,a){(b[g]||(b[g]=[])).push(c)});return this};a.prototype.off=function(a,c){var b=this.listeners;a.split(f).forEach(function(a,d){if(c){for(var e=b[a]||[];-1<(d=e.indexOf(c));)e.splice(d,1);b[a]=e}else b[a]=[]});return this};a.prototype.trigger=function(a){var c=this,b=Array.prototype.slice.call(arguments,0);a.split(f).forEach(function(a,
d){b[0]=a;var e=c.listeners[a];d=0;for(var f=e.length;e&&d<f;d++)e[d].apply(c,b)});return this}})(this);

example_usage.js

/**
 * Very basic usage example extracted from the original gist
 */
 
!function() {
  var eventable = new __.Eventable();
  
  var results = [];
  var callback = function test() { 
    var body = Array.prototype.slice.call(arguments, 0).join(' ');
    results.push(body);
  };
  var testEquals = function testEquals(name, val, desired) {
    if (val !== desired) {
      console.warn('failed test ' + name, 'got ' + val + ', expected:', desired);
    } else {
      console.log('passed test ' + name);
    }
    return val !== desired;    
  };
  
  var checkTrigger = function checkTrigger(txt) {
    var resultString = results.join(',');
    return testEquals('trigger ' + txt, txt, resultString);
  };
  
  // test event assignment
  eventable.on('test', callback);
  testEquals('event assignment', eventable.listeners['test'].length, 1);
  
  // test multiple event assignment
  eventable.on('multiple events', callback);
  testEquals('multiple event assignment (1st)', eventable.listeners['multiple'].length, 1);  
  testEquals('multiple event assignment (2nd)', eventable.listeners['events'].length, 1);    
  
  // check basic triggering
  eventable.trigger('test');
  checkTrigger('test');
  
  // check trigger with data
  eventable.trigger('test', 'extra data');
  checkTrigger('test,test extra data');
   
  // check trigger multiple events
  eventable.trigger('multiple events');
  checkTrigger('test,test extra data,multiple,events');
  
  // check trigger multiple events with extra data
  eventable.trigger('multiple events', 'more', 'data');
  checkTrigger('test,test extra data,multiple,events,multiple more data,events more data');
}();