Merge pull request #8 from shystruk/dev

initCustomEvent is deprecated

Author: shystruk

README.md

@@ -2,9 +2,9 @@
 [![MIT Licence](https://badges.frapsoft.com/os/mit/mit.svg?v=103)](https://opensource.org/licenses/mit-license.php) [![npm version](https://badge.fury.io/js/custom-event-js.svg)](https://badge.fury.io/js/custom-event-js)
 [![Known Vulnerabilities](https://snyk.io/test/github/shystruk/custom-event-js/badge.svg?targetFile=package.json)](https://snyk.io/test/github/shystruk/custom-event-js?targetFile=package.json)
 
-The Custom Event Dispatcher provides the ability to communicate inside your application by dispatching events and listening to them. It also runs polyfill for Internet Explorer 9 and higher. What is the CustomEvent interface you may find [here](https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent). 
+The Custom Event Dispatcher provides the ability to communicate inside your application by dispatching events and listening to them. What is the CustomEvent interface you may find [here](https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent).
 
-> **Custom Event Dispatcher works in all popular browsers, including Internet Explorer 9 and higher.**
+> **Custom Event Dispatcher works in all popular browsers**
 
 ## Install ##
 #### npm
@@ -27,14 +27,19 @@ CustomEvent.dispatch('SHOW_NAME', { name: 'GitHub' })
 
 // Remove event listener
 CustomEvent.off('SHOW_NAME')
+
+// Remove a specific callback from event listener
+CustomEvent.off('SHOW_NAME', callback)
 ```
 
 ## API
 - **on(eventName, callback)** add an appropriate event listener. When event gets fired callback will be called with **detail** argument
 
 - **dispatch(eventName, detail)** dispatch event to all event listeners
 
-- **off(eventName)** remove event listener
+- **off(eventName)** remove all event listeners for the event
+
+- **off(eventName, callback)** remove a specific event listener for the event
 
 
 ## Contributing

src/custom-event.js

@@ -1,6 +1,3 @@
-// Internet Explorer 9 and higher
-_CustomEventPolyfill();
-
 const TARGET = document;
 const EVENTS = {};
 
@@ -16,24 +13,6 @@ function _dispatchEvent(eventName, detail) {
 	TARGET.dispatchEvent(event);
 }
 
-function _CustomEventPolyfill() {
-	if (typeof window.CustomEvent === 'function') {
-		return;
-	}
-
-	function CustomEvent(event, params) {
-		const evt = document.createEvent('CustomEvent');
-
-		params = params || { bubbles: false, cancelable: false, detail: undefined };
-		evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
-
-		return evt;
-	}
-
-	CustomEvent.prototype = window.Event.prototype;
-	window.CustomEvent = CustomEvent;
-}
-
 module.exports = {
 	/**
 	 * @param {String} eventName
@@ -53,17 +32,33 @@ module.exports = {
 
 	/**
 	 * @param {String} eventName
+	 * @param {Function} callback
 	 */
-	off: function (eventName) {
+	off: function (eventName, callback) {
 		if (!EVENTS[eventName]) {
 			return;
 		}
 
-		EVENTS[eventName].callbacks.forEach(callback => {
-			TARGET.removeEventListener(eventName, callback);
-		});
+		const callbacks = EVENTS[eventName].callbacks;
+
+		if (callback) {
+			for (let i = callbacks.length - 1; i >= 0; i--) {
+				if (callbacks[i] === callback) {
+					TARGET.removeEventListener(eventName, callbacks[i]);
+					callbacks.splice(i, 1);
+				}
+			}
 
-		delete EVENTS[eventName];
+			if (callbacks.length === 0) {
+				delete EVENTS[eventName];
+			}
+		} else {
+			callbacks.forEach(callback => {
+				TARGET.removeEventListener(eventName, callback);
+			});
+
+			delete EVENTS[eventName];
+		}
 	},
 
 	/**