A small Class to create and manage custom javascript events

Installation

Browser

download JSEvents.min.js and add to the sript in the head tag of your web application.

<script type="text/javascript" src="path-to-JSevents.min.js">

Node

npm install jsevents-js

var JSEvents = require('jsevents-js');

API

1. addEventListener

/**
 * @name addEventListener
 * @param {string} name
 * @param {function} callback
 * @param {object} scope
 * @description this function registeres the event
 * @returns {null} this function does not return anything
 */
 JSEvents.addEventListener(type,callback,scope);

2. removeEventListener

 /**
   * @name removeEventListener
   * @param {string} name
   * @param {function} callback
   * @param {object} scope
   * @description this function will remove registered the event
   * @returns {null} this function does not return anything
   */
   JSEvents.removeEventListener(type,callback,scope);

3. hasEventListener

/**
   * @name hasEventListener
   * @param {string} name
   * @param {function} callback
   * @param {object} scope
   * @description this function check and return true/false if the event has
   * any registered listener
   * @returns {boolean} return true if the event has any listener
   */
   var result = JSEvents.hasEventListener(name,callback,scope);

4. dispatchEvent

/**
 * @name dispatchEvent
 * @param {string} name
 * @param {any} data
 * @description this function check and return true/false if the event has
 * any registered listener
 * @returns {null} this function will fire the registered event
 */
 JSEvents.dispatchEvent(name,data)

5. getRegisteredEvents

/**
   * @name getRegisteredEvents
   * @description this function return all the events registered in the store
   * @returns {object} this getter will return all the registered events
   */
   var allEvents=JSEvents.getRegisteredEvents()

Usage

 var testOb={
    add:function(){
       // last parameter is the scope.
       // all params are mandatory
        JSEvents.addEventListener('TEST_OB_FN',this.cb,this);
    },
    dispatch:function(){
        JSEvents.dispatchEvent('TEST_OB_FN','hi')
    },
    cb:function(event,data){
        console.log(data)
    },
    getAll:function(){
        console.log(JSEvents.getRegisteredEvents())
    }
    remove:function(){
      // all are mendatory
      JSEvents.removeEventListener('TEST_OB_FN',this.cb,this);
    }
}
testOb.add();
testOb.dispatch();
testOb.getAll();

passing extra parameters

   var cb=function(event,param1,param2,param3,param4){
     console.log(param1,param2,param3,param4);
   }
   JSEvents.addEventListener('NAME',cb,window);
   JSEvents.dispatchEvent('NAME','hi','anything','nothing',[1,2,3]);
   

Important

it is very important to not to declare the function callback inside the calling block. make sure you always declare the function as a variable and pass the variable to the addEventListener or removeEventListener

JSEvents.addEventListener('NAME',function(){
  // this is wrong.
},window);

JSEvents.removeEventListener('NAME',function(){
  // this is wrong.
},window);

var cb=function(ev){

}
JSEvents.addEventListener('NAME',cb,window); // this is correct
JSEvents.removeEventListener('NAME',cb,window); // this is correct