eventemitter3 - npm Package Compare versions

Comparing version 0.1.6 to 1.0.0

index.js

@@ -38,11 +38,16 @@ 'use strict';
  * @param {String} event The events that should be listed.
- * @returns {Array}
+ * @param {Boolean} exists We only need to know if there are listeners.
+ * @returns {Array|Boolean}
  * @api public
  */
-EventEmitter.prototype.listeners = function listeners(event) {
-  if (!this._events || !this._events[event]) return [];
-  if (this._events[event].fn) return [this._events[event].fn];
+EventEmitter.prototype.listeners = function listeners(event, exists) {
+  var prefix = '~'+ event
+    , available = this._events && this._events[prefix];
 
-  for (var i = 0, l = this._events[event].length, ee = new Array(l); i < l; i++) {
-    ee[i] = this._events[event][i].fn;
+  if (exists) return !!available;
+  if (!available) return [];
+  if (this._events[prefix].fn) return [this._events[prefix].fn];
+
+  for (var i = 0, l = this._events[prefix].length, ee = new Array(l); i < l; i++) {
+    ee[i] = this._events[prefix][i].fn;
   }
@@ -61,5 +66,7 @@
 EventEmitter.prototype.emit = function emit(event, a1, a2, a3, a4, a5) {
-  if (!this._events || !this._events[event]) return false;
+  var prefix = '~'+ event;
 
-  var listeners = this._events[event]
+  if (!this._events || !this._events[prefix]) return false;
+
+  var listeners = this._events[prefix]
     , len = arguments.length
@@ -70,3 +77,3 @@ , args
   if ('function' === typeof listeners.fn) {
-    if (listeners.once) this.removeListener(event, listeners.fn, true);
+    if (listeners.once) this.removeListener(event, listeners.fn, undefined, true);
 
@@ -92,3 +99,3 @@ switch (len) {
     for (i = 0; i < length; i++) {
-      if (listeners[i].once) this.removeListener(event, listeners[i].fn, true);
+      if (listeners[i].once) this.removeListener(event, listeners[i].fn, undefined, true);
 
@@ -121,10 +128,11 @@ switch (len) {
 EventEmitter.prototype.on = function on(event, fn, context) {
-  var listener = new EE(fn, context || this);
+  var listener = new EE(fn, context || this)
+    , prefix = '~'+ event;
 
   if (!this._events) this._events = {};
-  if (!this._events[event]) this._events[event] = listener;
+  if (!this._events[prefix]) this._events[prefix] = listener;
   else {
-    if (!this._events[event].fn) this._events[event].push(listener);
-    else this._events[event] = [
-      this._events[event], listener
+    if (!this._events[prefix].fn) this._events[prefix].push(listener);
+    else this._events[prefix] = [
+      this._events[prefix], listener
     ];
@@ -145,10 +153,11 @@ }
 EventEmitter.prototype.once = function once(event, fn, context) {
-  var listener = new EE(fn, context || this, true);
+  var listener = new EE(fn, context || this, true)
+    , prefix = '~'+ event;
 
   if (!this._events) this._events = {};
-  if (!this._events[event]) this._events[event] = listener;
+  if (!this._events[prefix]) this._events[prefix] = listener;
   else {
-    if (!this._events[event].fn) this._events[event].push(listener);
-    else this._events[event] = [
-      this._events[event], listener
+    if (!this._events[prefix].fn) this._events[prefix].push(listener);
+    else this._events[prefix] = [
+      this._events[prefix], listener
     ];
@@ -165,9 +174,12 @@ }
  * @param {Function} fn The listener that we need to find.
+ * @param {Mixed} context Only remove listeners matching this context.
  * @param {Boolean} once Only remove once listeners.
  * @api public
  */
-EventEmitter.prototype.removeListener = function removeListener(event, fn, once) {
-  if (!this._events || !this._events[event]) return this;
+EventEmitter.prototype.removeListener = function removeListener(event, fn, context, once) {
+  var prefix = '~'+ event;
 
-  var listeners = this._events[event]
+  if (!this._events || !this._events[prefix]) return this;
+
+  var listeners = this._events[prefix]
     , events = [];
@@ -180,3 +192,7 @@
     if (!listeners.fn) for (var i = 0, length = listeners.length; i < length; i++) {
-      if (listeners[i].fn !== fn || (once && !listeners[i].once)) {
+      if (
+           listeners[i].fn !== fn
+        || (once && !listeners[i].once)
+        || (context && listeners[i].context !== context)
+      ) {
         events.push(listeners[i]);
@@ -191,5 +207,5 @@ }
   if (events.length) {
-    this._events[event] = events.length === 1 ? events[0] : events;
+    this._events[prefix] = events.length === 1 ? events[0] : events;
   } else {
-    delete this._events[event];
+    delete this._events[prefix];
   }
@@ -209,3 +225,3 @@
 
-  if (event) delete this._events[event];
+  if (event) delete this._events['~'+ event];
   else this._events = {};
@@ -232,9 +248,2 @@
 //
-EventEmitter.EventEmitter = EventEmitter;
-EventEmitter.EventEmitter2 = EventEmitter;
-EventEmitter.EventEmitter3 = EventEmitter;
-
-//
-// Expose the module.
-//
 module.exports = EventEmitter;

package.json

 {
   "name": "eventemitter3",
-  "version": "0.1.6",
+  "version": "1.0.0",
   "description": "EventEmitter3 focuses on performance while maintaining a Node.js AND browser compatible interface.",
   "main": "index.js",
   "scripts": {
-    "test": "mocha --reporter spec --ui bdd test.js",
-    "coverage": "istanbul cover ./node_modules/.bin/_mocha -- --reporter spec --ui bdd test.js",
-    "test-travis": "istanbul cover node_modules/.bin/_mocha --report lcovonly -- --reporter spec test.js"
+    "test": "mocha test.js",
+    "coverage": "istanbul cover ./node_modules/.bin/_mocha -- test.js",
+    "test-travis": "istanbul cover node_modules/.bin/_mocha --report lcovonly -- test.js"
   },
@@ -38,7 +38,7 @@ "repository": {
   "devDependencies": {
-    "assume": "0.0.x",
+    "assume": "1.2.x",
     "istanbul": "0.3.x",
-    "mocha": "2.0.x",
-    "pre-commit": "0.0.x"
+    "mocha": "2.2.x",
+    "pre-commit": "1.0.x"
   }
 }

README.md

 # EventEmitter3
 
-[![Version npm](http://img.shields.io/npm/v/eventemitter3.svg?style=flat-square)](http://browsenpm.org/package/eventemitter3)[![Build Status](http://img.shields.io/travis/primus/EventEmitter3/master.svg?style=flat-square)](https://travis-ci.org/primus/EventEmitter3)[![Dependencies](https://img.shields.io/david/primus/EventEmitter3.svg?style=flat-square)](https://david-dm.org/primus/EventEmitter3)[![Coverage Status](http://img.shields.io/coveralls/primus/EventEmitter3/master.svg?style=flat-square)](https://coveralls.io/r/primus/EventEmitter3?branch=master)[![IRC channel](http://img.shields.io/badge/IRC-irc.freenode.net%23primus-00a8ff.svg?style=flat-square)](http://webchat.freenode.net/?channels=primus)
+[![Version npm](https://img.shields.io/npm/v/eventemitter3.svg?style=flat-square)](http://browsenpm.org/package/eventemitter3)[![Build Status](https://img.shields.io/travis/primus/eventemitter3/master.svg?style=flat-square)](https://travis-ci.org/primus/eventemitter3)[![Dependencies](https://img.shields.io/david/primus/eventemitter3.svg?style=flat-square)](https://david-dm.org/primus/eventemitter3)[![Coverage Status](https://img.shields.io/coveralls/primus/eventemitter3/master.svg?style=flat-square)](https://coveralls.io/r/primus/eventemitter3?branch=master)[![IRC channel](https://img.shields.io/badge/IRC-irc.freenode.net%23primus-00a8ff.svg?style=flat-square)](https://webchat.freenode.net/?channels=primus)
 
-EventEmitter3 is a faster alternative to EventEmitter2 and the built-in
-EventEmitter that ships within Node.js. It removes some features that you might
-not need:
+EventEmitter3 is a high performance EventEmitter. It has been micro-optimized
+for various of code paths making this one of the, if not the fastest
+EventEmitter available for Node.js and browsers. The module is API compatible
+with the EventEmitter that ships by default within Node.js but there are some
+slight differences:
 
-- Domain support.
-- Thrown errors when there are no error listeners specified.
-- That a `newListener` event is emitted when an event is emitted.
-- No silly `setMaxListeners`, the function exists, but does nothing.
-- No silly `listenerCount` function.. Just do `EventEmitter.listeners(event).length`
+- Domain support has been removed.
+- We do not `throw` an error when you emit an `error` event and nobody is
+  listening.
+- The `newListener` event is removed as the use-cases for this functionality are
+  really just edge cases.
+- No `setMaxListeners` and it's pointless memory leak warnings. If you want to
+  add `end` listeners you should be able to do that without modules complaining.
+- No `listenerCount` function. Use `EE.listeners(event).length` instead.
+- Support for custom context for events so there is no more `fn.bind` required.
+- `listeners` method can now do existence checking instead returning full arrays
 
-And adds some features you want:
+It's a drop in replacement for existing EventEmitters, but just faster. Free
+performance, who wouldn't want that? The EventEmitter is written in EcmaScript 3
+so it will work in the oldest browsers and node versions that you need to
+support.
 
-- Emit events with a custom context without binding: `EE.on(event, fn, context)`
-  which also works with once `EE.once(event, fn, context)`
-
-It's a drop in replacement of your existing EventEmitters, but just faster. Free
-performance, who wouldn't want that?
-
-The source of the EventEmitter is compatible for browser usage, no fancy pancy
-`Array.isArray` stuff is used, it's just plain ol JavaScript that should even
-work IE5 if you want to.
-
 ## Installation
 
 ```bash
-$ npm install --save eventemitter3
+$ npm install --save eventemitter3        # npm
+$ component install primus/eventemitter3  # Component
+$ bower install primus/eventemitter3      # Bower
 ```
-or as a [component](http://component.io)
 
-```bash
-$ component install eventemitter3
-```
+## Usage
 
-then
+After installation the only thing you need to do is require the module:
 
 ```js
 var EventEmitter = require('eventemitter3');
+```
 
-// or
+And you're ready to create your own EventEmitter instances. For the API
+documentation, please follow the official Node.js documentation:
 
-var EventEmitter = require('eventemitter3').EventEmitter;
+http://nodejs.org/api/events.html
+
+### Contextual emits
+
+We've upgraded the API of the `EventEmitter.on`, `EventEmitter.once` and
+`EventEmitter.removeListener` to accept an extra argument which is the `context`
+or `this` value that should be set for the emitted events. This means you no
+longer have the overhead of an event that required `fn.bind` in order to get a
+custom `this` value.
+
+```js
+var EE = new EventEmitter()
+  , context = { foo: 'bar' };
+
+function emitted() {
+  console.log(this === context); // true
+}
+
+EE.once('event-name', emitted, context);
+EE.on('another-event', emitted, context);
+EE.removeListener('another-event', emitted, context);
 ```
 
-For API methods see the official Node.js documentation:
+### Existence
 
-http://nodejs.org/api/events.html
+To check if there is already a listener for a given event you can supply the
+`listeners` method with an extra boolean argument. This will transform the
+output from an array, to a boolean value which indicates if there are listeners
+in place for the given event:
+
+```js
+var EE = new EventEmitter();
+EE.once('event-name', function () {});
+EE.on('another-event', function () {});
+
+EE.listeners('event-name', true); // returns true
+EE.listeners('unknown-name', true); // returns false
+```
+
+## License
+
+MIT

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