Exposed Evented#_hooksEvent as public #hooksEvent

src/event/Evented.js

@@ -193,7 +193,7 @@ module.exports = Trait( 'Evented',
         else if ( typeof listener !== 'function' ) {
             throw TypeError( "Event listener must be a function" );
         }
-        else if ( this._hooksEvent( ev, listener ) )
+        else if ( this.hooksEvent( ev, listener ) )
         {
             throw Error(
                 `Listener has already been bound to event \`${ev}'`
@@ -260,10 +260,10 @@ module.exports = Trait( 'Evented',
      *
      * @return {boolean} whether LISTENER hooks event EV
      */
-    _hooksEvent( ev, listener )
+    hooksEvent( ev, listener )
     {
         let levdata = listener[ _evid ];
-        return ( levdata && ( levdata[ ev ] !== undefined ) );
+        return !!( levdata && ( levdata[ ev ] !== undefined ) );
     },
 
 

test/event/EventedTest.js

@@ -597,5 +597,54 @@ describe( 'event.Evented', () =>
             } );
         } );
     } );
+
+
+    describe( '#hooksEvent', () =>
+    {
+        var ev = 'foo',
+            f;
+
+        beforeEach( () =>
+        {
+            // ensure fresh listener
+            f = () => {};
+        } );
+
+
+        it( 'recognizes listener for a hooked event', () =>
+        {
+            stub.evDefineEvents( [ ev ] )
+                .on( ev, f );
+
+            expect( stub.hooksEvent( ev, f ) ).to.be.true;
+        } );
+
+
+        it( 'does not recognize listener for non-hooked event', () =>
+        {
+            expect( stub.hooksEvent( ev, f ) ).to.be.false;
+        } );
+
+
+        /**
+         * Technically this test is sufficient to make the previous two
+         * redundant, but they are retained for clairty in debugging.
+         */
+        it( 'does not recognize listeners of other events', () =>
+        {
+            var ev2 = 'bar',
+                f2  = () => {};
+
+            stub.evDefineEvents( [ ev, ev2 ] )
+                .on( ev, f )
+                .on( ev2, f2 );
+
+            expect( stub.hooksEvent( ev, f ) ).to.be.true;
+            expect( stub.hooksEvent( ev2, f ) ).to.be.false;
+
+            expect( stub.hooksEvent( ev, f2 ) ).to.be.false;
+            expect( stub.hooksEvent( ev2, f2 ) ).to.be.true;
+        } );
+    } );
 } );