Added Emitter#has(event)

Readme.md

@@ -29,3 +29,7 @@ $ npm install emitter-component
 ### Emitter#emit(event, ...)
 
   Emit an `event` with variable option args.
+
+### Emitter#has(event)
+
+  Check if this emitter has `event` handlers.

index.js

@@ -98,3 +98,9 @@ Emitter.prototype.emit = function(event){
 
   return this;
 };
+
+Emitter.prototype.has = function(event){
+  var fns = this.callbacks[event];
+  return !!(fns && fns.length);
+};
+

test/emitter.js

@@ -77,4 +77,21 @@ describe('Emitter', function(){
       calls.should.eql([]);
     })
   })
+
+  describe('.has(event)', function(){
+    describe('when handlers are present', function(){
+      it('should return true', function(){
+        var emitter = new Emitter;
+        emitter.on('foo', function(){});
+        emitter.has('foo').should.be.true;
+      })
+    })
+
+    describe('when no handlers are present', function(){
+      it('should return false', function(){
+        var emitter = new Emitter;
+        emitter.has('foo').should.be.false;
+      })
+    })
+  })
 })