Filterable: fix preventDefault not working

Closes gh-7154
Fixes gh-7153

(cherry picked from commit 6b46425)

Author: frequent

js/widgets/filterable.backcompat.js

@@ -72,7 +72,9 @@ $.widget( "mobile.filterable", $.mobile.filterable, {
 			// Also trigger listviewbeforefilter if this widget is also a listview
 			this._widget._trigger( "beforefilter", event, data );
 		}
-		this._super( type, event, data );
+
+		// Passing back the response enables calling preventDefault()
+		return this._super( type, event, data );
 	},
 
 	_setWidget: function( widget ) {

js/widgets/filterable.js

@@ -62,7 +62,9 @@ $.widget( "mobile.filterable", {
 			}
 
 			this._timer = this._delay( function() {
-				this._trigger( "beforefilter", null, { input: search } );
+				if ( this._trigger( "beforefilter", null, { input: search } ) === false ) {
+					return false;
+				}
 
 				// Change val as lastval for next execution
 				search[ 0 ].setAttribute( "data-" + $.mobile.ns + "lastval", val );

tests/integration/filterable/filterable_core.js

@@ -67,6 +67,29 @@
 		], 500 );
 	});
 
+	asyncTest( "Filter won't run when preventing default on 'filterablebeforefilter'", function() {
+		expect( 1 );
+
+		var input = $( "#test-prevent-default-handler" ),
+			listview = $( "#test-prevent-default-signal-emission" );
+
+		listview.on( "filterablebeforefilter.theEventIsPrevented", function (e) {
+			e.preventDefault();
+		});
+
+		$.testHelper.sequence([
+			function() {
+				input.val( "a" ).trigger( "change" );
+			},
+			function() {
+				deepEqual( listview.children( ".ui-screen-hidden" ).length, 0,
+					"No children are hidden." );
+				listview.off( "filterablebeforefilter.theEventIsPrevented" );
+			},
+			start
+		], 500);
+	});
+
 	asyncTest( "filterCallback and filterReveal can be altered after widget creation", function(){
 		var filterable = $( "#custom-callback-listview" ),
 			input = $( "#custom-callback-listview-input" ),

tests/integration/filterable/index.html

@@ -93,6 +93,17 @@ <h1>Filterable</h1>
 				<li>d is for darkwing</li>
 			</ul>
 
+			<input id="test-prevent-default-handler"></input>
+			<ul id="test-prevent-default-signal-emission"
+				data-nstest-role="listview"
+				data-nstest-filter="true"
+				data-nstest-input="#test-prevent-default-handler">
+				<li>San Francisco, CA</li>
+				<li>Portland, OR</li>
+				<li>Washington, DC</li>
+				<li>New York, NY</li>
+			</ul>
+
 			<input id="custom-callback-listview-input"></input>
 			<ul id="custom-callback-listview" data-nstest-role="listview" data-nstest-filter="true" data-nstest-input="#custom-callback-listview-input">
 				<li>a is for aquaman</li>