Preserves context objects when multiple Deferreds are passed to $.when()....

Preserves context objects when multiple Deferreds are passed to $.when(). Context is an array containing the original contexts in order. When non-observable value is given, associated context is undefined. In case only a single non-observable value is given, context is the global object (thanks so much Function.prototype.apply!). Fixes #11749.

src/deferred.js

@@ -97,35 +97,39 @@ jQuery.extend({
 		var i = 0,
 			resolveValues = sliceDeferred.call( arguments ),
 			length = resolveValues.length,
-			progressValues = new Array( length ),
 
 			// the count of uncompleted subordinates
 			remaining = length !== 1 || ( subordinate && jQuery.isFunction( subordinate.promise ) ) ? length : 0,
 
 			// the master Deferred. If resolveValues consist of only a single Deferred, just use that.
 			deferred = remaining === 1 ? subordinate : jQuery.Deferred(),
-			promise = deferred.promise(),
 
 			// Update function for both resolve and progress values
-			updateFunc = function( i, arr ) {
+			updateFunc = function( i, contexts, values ) {
 				return function( value ) {
-					arr[ i ] = arguments.length > 1 ? sliceDeferred.call( arguments ) : value;
-					if( arr === progressValues ) {
-						deferred.notifyWith( promise, arr );
+					contexts[ i ] = this;
+					values[ i ] = arguments.length > 1 ? sliceDeferred.call( arguments ) : value;
+					if( values === progressValues ) {
+						deferred.notifyWith( contexts, values );
 					} else if ( !( --remaining ) ) {
-						deferred.resolveWith( promise, arr );
+						deferred.resolveWith( contexts, values );
 					}
 				};
-			};
+			},
+			
+			progressValues, progressContexts, resolveContexts;
 
 		// add listeners to Deferred subordinates; treat others as resolved
 		if ( length > 1 ) {
+			progressValues = new Array( length );
+			progressContexts = new Array( length );
+			resolveContexts = new Array( length );
 			for ( ; i < length; i++ ) {
 				if ( resolveValues[ i ] && jQuery.isFunction( resolveValues[ i ].promise ) ) {
 					resolveValues[ i ].promise()
-						.done( updateFunc( i, resolveValues ) )
+						.done( updateFunc( i, resolveContexts, resolveValues ) )
 						.fail( deferred.reject )
-						.progress( updateFunc( i, progressValues ) );
+						.progress( updateFunc( i, progressContexts, progressValues ) );
 				} else {
 					--remaining;
 				}
@@ -134,10 +138,10 @@ jQuery.extend({
 
 		// if we're not waiting on anything, resolve the master
 		if ( !remaining ) {
-			deferred.resolveWith( deferred, resolveValues );
+			deferred.resolveWith( resolveContexts, resolveValues );
 		}
 
-		return promise;
+		return deferred.promise();
 	}
 });
 

test/unit/deferred.js

@@ -289,7 +289,7 @@ test( "jQuery.Deferred.then - context", function() {
 
 test( "jQuery.when" , function() {
 
-	expect( 23 );
+	expect( 34 );
 
 	// Some other objects
 	jQuery.each( {
@@ -307,15 +307,23 @@ test( "jQuery.when" , function() {
 	} , function( message , value ) {
 
 		ok( jQuery.isFunction( jQuery.when( value ).done(function( resolveValue ) {
+			strictEqual( this, window, "Context is the global object with " + message );
 			strictEqual( resolveValue , value , "Test the promise was resolved with " + message );
 		}).promise ) , "Test " + message + " triggers the creation of a new Promise" );
 
 	} );
 
 	ok( jQuery.isFunction( jQuery.when().done(function( resolveValue ) {
-		strictEqual( resolveValue , undefined , "Test the promise was resolved with no parameter" );
+		strictEqual( this, window, "Test the promise was resolved with window as its context" );
+		strictEqual( resolveValue, undefined, "Test the promise was resolved with no parameter" );
 	}).promise ) , "Test calling when with no parameter triggers the creation of a new Promise" );
 
+	var context = {};
+
+	jQuery.when( jQuery.Deferred().resolveWith( context ) ).done(function() {
+		strictEqual( this, context, "when( promise ) propagates context" );
+	});
+
 	var cache, i;
 
 	for( i = 1 ; i < 4 ; i++ ) {
@@ -330,7 +338,7 @@ test( "jQuery.when" , function() {
 
 test("jQuery.when - joined", function() {
 
-	expect(53);
+	expect( 119 );
 
 	var deferreds = {
 			value: 1,
@@ -362,11 +370,15 @@ test("jQuery.when - joined", function() {
 				shouldNotify = willNotify[ id1 ] || willNotify[ id2 ],
 				expected = shouldResolve ? [ 1, 1 ] : [ 0, undefined ],
 			    expectedNotify = shouldNotify && [ willNotify[ id1 ], willNotify[ id2 ] ],
-			    code = id1 + "/" + id2;
+			    code = id1 + "/" + id2,
+			    context1 = defer1 && jQuery.isFunction( defer1.promise ) ? defer1 : undefined,
+			    context2 = defer2 && jQuery.isFunction( defer2.promise ) ? defer2 : undefined;
 
-			var promise = jQuery.when( defer1, defer2 ).done(function( a, b ) {
+			jQuery.when( defer1, defer2 ).done(function( a, b ) {
 				if ( shouldResolve ) {
 					deepEqual( [ a, b ], expected, code + " => resolve" );
+					strictEqual( this[ 0 ], context1, code + " => first context OK" );
+					strictEqual( this[ 1 ], context2, code + " => second context OK" );
 				} else {
 					ok( false ,  code + " => resolve" );
 				}
@@ -376,8 +388,10 @@ test("jQuery.when - joined", function() {
 				} else {
 					ok( false ,  code + " => reject" );
 				}
-			}).progress(function progress( a, b ) {
+			}).progress(function( a, b ) {
 				deepEqual( [ a, b ], expectedNotify, code + " => progress" );
+				strictEqual( this[ 0 ], expectedNotify[ 0 ] ? context1 : undefined, code + " => first context OK" );
+				strictEqual( this[ 1 ], expectedNotify[ 1 ] ? context2 : undefined, code + " => second context OK" );
 			});
 		} );
 	} );