Initial commit

index.js

@@ -0,0 +1,100 @@
+
+/**
+ * Expose `Emitter`.
+ */
+
+module.exports = Emitter;
+
+/**
+ * Initialize a new `Emitter`.
+ * 
+ * @api public
+ */
+
+function Emitter() {
+  this.callbacks = {};
+};
+
+/**
+ * Listen on the given `event` with `fn`.
+ *
+ * @param {String} event
+ * @param {Function} fn
+ * @return {Emitter}
+ * @api public
+ */
+
+Emitter.prototype.on = function(event, fn){
+  (this.callbacks[event] = this.callbacks[event] || [])
+    .push(fn);
+  return this;
+};
+
+/**
+ * Adds an `event` listener that will be invoked a single
+ * time then automatically removed.
+ *
+ * @param {String} event
+ * @param {Function} fn
+ * @return {Emitter}
+ * @api public
+ */
+
+Emitter.prototype.once = function(event, fn){
+  var self = this;
+
+  function on() {
+    self.off(event, on);
+    fn.apply(this, arguments);
+  }
+
+  this.on(event, on);
+  return this;
+};
+
+/**
+ * Remove the given callback for `event` or all
+ * registered callbacks.
+ *
+ * @param {String} event
+ * @param {Function} fn
+ * @return {Emitter}
+ * @api public
+ */
+
+Emitter.prototype.off = function(event, fn){
+  var callbacks = this.callbacks[event];
+  if (!callbacks) return this;
+
+  // remove all handlers
+  if (1 == arguments.length) {
+    delete this.callbacks[event];
+    return this;
+  }
+
+  // remove specific handler
+  var i = callbacks.indexOf(fn);
+  callbacks.splice(i, 1);
+  return this;
+};
+
+/**
+ * Emit `event` with the given args.
+ *
+ * @param {String} event
+ * @param {Mixed} ...
+ * @return {Emitter} 
+ */
+
+Emitter.prototype.emit = function(event){
+  var args = [].slice.call(arguments, 1)
+    , callbacks = this.callbacks[event];
+
+  if (callbacks) {
+    for (var i = 0, len = callbacks.length; i < len; ++i) {
+      callbacks[i].apply(this, args);
+    }
+  }
+
+  return this;
+};

package.json

@@ -0,0 +1,10 @@
+{
+  "name": "emitter",
+  "description": "Event emitter",
+  "version": "0.0.1",
+  "component": {
+    "scripts": {
+      "emitter": "index.js"
+    }
+  }
+}