lazyemitter.js

//   getEvents()

// Keep a track of the events list for each element

//   getListeners(event)

// Keep a track of the listener list for each event

/* ===================Handle adding of event=================== */

//   addEventsListeners(element, event, listener or array_of_listeners)

// If a new event with a listener is added
//   Make the first item in list to be the DOM element
//   Check if the event is already in list or create it
//   Add the listener to the list corresponding to the event
// Else
//   Add the event to the event list and the listener to a new listener list for the event
// EndIf

/* ===================Handle firing of event=================== */

//  emitEvent(element, event, options)
//    options = { timeIntervalBetweenEachListener (defaults to 500ms), numberOfListeners (defaults to all) }

// For an event check if the event exists in list on the element
//   If event exists
//     Check if the numberOfListeners are provided else call all the listeners
//   Else
//     Throw Error
//   Endif

/* ===================Remove events=================== */

//  removeEventsListeners(event)

// Get the List of Events
// If event is specified
//   remove the event from the list of events
// Else
//   remove all events
// Endif

;var vcr = (function() {

  function classOf(whatever) {
    return Object.prototype.toString.call(whatever).slice(8, -1)
  }

  function $(sel) {
    var dom = document.querySelectorAll(sel);
    if(classOf(sel) == "String") {
      return dom.length ==1 ? dom[0] : [].slice.call(dom)
    }
    else if(sel instanceof HTMLElement) {
      return sel
    }

    else {
      throw new Error("Feature not supported!!")
    }
  }


  return {
    getEvents: function() {
      return this.events || (this.events = {})
    },

    getListeners: function(element, event) {
      element = element || "body";
      this.events[element] = this.events[element] || {}

      return this.events[element][event]  || (this.events[element][event] = [])

    },

    addEventsListeners: function(element, event, listeners) {
      var events = this.getEvents()
      , eventListeners = this.getListeners(element, event)
      ;

      if(classOf(listeners) === 'Function') {
        eventListeners.push(listeners);

      } else if(Array.isArray(listeners)) {
        for(var i = 0, len = eventListeners.length; i < len; i++) {
          this.addEventsListeners(element, event, eventListeners[i])
        }
      } else {
        throw new Error("Need function or array of functions")
      }

    },

    emitEvent: function(element, event, options) {
      var timeOut       = options && options.timeOut || 500
      ,  limit          = options && options.limit || 0
      ,  eventListeners = this.getListeners(element, event)
      ,  element        = $(element)
      ;

      for(var i = 0, len = eventListeners.length - limit; len > 0 && i < len; i++) {
        var evt = new Event(event)
        element.addEventListener(event, eventListeners[i]);
        element.dispatchEvent(evt);
      }

    }

  }

}());

vcr.addEventsListeners("body", "click", function(e) { console.log(1) });
vcr.emitEvent("body", "click");