refactor: migrate EmitterWrapped to ES2015

lib/emitter_wrapper.js

@@ -1,31 +1,38 @@
-function EmitterWrapper (emitter) {
-  this.listeners = {}
-  this.emitter = emitter
-}
-
-EmitterWrapper.prototype.addListener = EmitterWrapper.prototype.on = function (event, listener) {
-  this.emitter.addListener(event, listener)
+'use strict'
 
-  if (!this.listeners.hasOwnProperty(event)) {
-    this.listeners[event] = []
+class EmitterWrapper {
+  constructor (emitter) {
+    this.listeners = {}
+    this.emitter = emitter
   }
 
-  this.listeners[event].push(listener)
+  addListener (event, listener) {
+    this.emitter.addListener(event, listener)
 
-  return this
-}
+    if (!this.listeners.hasOwnProperty(event)) {
+      this.listeners[event] = []
+    }
 
-EmitterWrapper.prototype.removeAllListeners = function (event) {
-  var events = event ? [event] : Object.keys(this.listeners)
-  var self = this
-  events.forEach(function (event) {
-    self.listeners[event].forEach(function (listener) {
-      self.emitter.removeListener(event, listener)
+    this.listeners[event].push(listener)
+
+    return this
+  }
+
+  on (event, listener) {
+    return this.addListener(event, listener)
+  }
+
+  removeAllListeners (event) {
+    const events = event ? [event] : Object.keys(this.listeners)
+    events.forEach((event) => {
+      this.listeners[event].forEach((listener) => {
+        this.emitter.removeListener(event, listener)
+      })
+      delete this.listeners[event]
     })
-    delete self.listeners[event]
-  })
 
-  return this
+    return this
+  }
 }
 
 module.exports = EmitterWrapper

test/unit/emitter_wrapper.spec.js

@@ -1,10 +1,11 @@
-var EventEmitter = require('events').EventEmitter
+'use strict'
 
-var EmitterWrapper = require('../../lib/emitter_wrapper')
+const EventEmitter = require('events').EventEmitter
+const EmitterWrapper = require('../../lib/emitter_wrapper')
 
 describe('emitter_wrapper', () => {
-  var emitter
-  var wrapped
+  let emitter
+  let wrapped
 
   beforeEach(() => {
     emitter = new EventEmitter()
@@ -14,7 +15,7 @@ describe('emitter_wrapper', () => {
   })
 
   describe('addListener', () => {
-    var aListener = (e) => true
+    const aListener = (e) => true
 
     it('should add a listener to the wrapped emitter', () => {
       wrapped.addListener('anEvent', aListener)
@@ -27,7 +28,7 @@ describe('emitter_wrapper', () => {
   })
 
   describe('removeAllListeners', () => {
-    var aListener = (e) => true
+    const aListener = (e) => true
 
     beforeEach(() => {
       wrapped.addListener('anEvent', aListener)
@@ -44,7 +45,7 @@ describe('emitter_wrapper', () => {
     })
 
     it('should remove only matching listeners when called with an event name', () => {
-      var anotherListener = (e) => true
+      const anotherListener = (e) => true
       wrapped.addListener('anotherEvent', anotherListener)
       wrapped.removeAllListeners('anEvent')
       expect(emitter.listeners('anEvent')).not.to.contain(aListener)