Merge pull request #183 from emschwartz/master

Add listenerCount method
EventEmitter2 · Aug 4, 2016 · 35a56ed · 35a56ed
2 parents bb6ffd5 + ecc2044
commit 35a56ed
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diff --git a/lib/eventemitter2.js b/lib/eventemitter2.js
@@ -694,6 +694,10 @@
     return this._events[type];
   };
 
+  EventEmitter.prototype.listenerCount = function(type) {
+    return this.listeners(type).length;
+  };
+
   EventEmitter.prototype.listenersAny = function() {
 
     if(this._all) {

diff --git a/test/simple/addListener.js b/test/simple/addListener.js
@@ -194,5 +194,29 @@ module.exports = simpleEvents({
     test.expect(2);
     test.done();
 
+  },
+
+  '11. listenerCount should return the number of listeners': function (test) {
+
+
+    var emitter = new EventEmitter2({ verbose: true });
+
+    test.equal(emitter.listenerCount('test1'), 0, 'Before adding listeners listenerCount is 0')
+
+    emitter.on('test1', function () {
+      test.ok(true, 'The event was raised');
+    });
+
+    test.equal(emitter.listenerCount('test1'), 1, 'After adding a listener listenerCount is 1')
+
+    emitter.on('test1', function () {
+      test.ok(true, 'The event was raised');
+    });
+
+    test.equal(emitter.listeners('test1').length, 2, 'And then there were 2');
+
+    test.expect(3);
+    test.done();
+
   }
 });