Makes Deferred implementation truly Promise/A compliant. Unit tests amended....

Makes Deferred implementation truly Promise/A compliant. Unit tests amended. Actually few changes required in jQuery's own source and we gained 8 bytes minified gzipped \o/.

src/ajax.js

@@ -609,7 +609,7 @@ jQuery.extend({
 					}
 				} else {
 					tmp = map[ jqXHR.status ];
-					jqXHR.then( tmp, tmp );
+					jqXHR.always( tmp );
 				}
 			}
 			return this;

src/deferred.js

@@ -28,15 +28,11 @@ jQuery.extend({
 				isResolved: doneList.fired,
 				isRejected: failList.fired,
 
-				then: function( doneCallbacks, failCallbacks, progressCallbacks ) {
-					deferred.done( doneCallbacks ).fail( failCallbacks ).progress( progressCallbacks );
-					return this;
-				},
 				always: function() {
 					deferred.done.apply( deferred, arguments ).fail.apply( deferred, arguments );
 					return this;
 				},
-				pipe: function( fnDone, fnFail, fnProgress ) {
+				then: function( fnDone, fnFail, fnProgress ) {
 					return jQuery.Deferred(function( newDefer ) {
 						jQuery.each( {
 							done: [ fnDone, "resolve" ],
@@ -50,7 +46,7 @@ jQuery.extend({
 								deferred[ handler ](function() {
 									returned = fn.apply( this, arguments );
 									if ( returned && jQuery.isFunction( returned.promise ) ) {
-										returned.promise().then( newDefer.resolve, newDefer.reject, newDefer.notify );
+										returned.promise().done( newDefer.resolve ).fail( newDefer.reject ).progress( newDefer.notify );
 									} else {
 										newDefer[ action + "With" ]( this === deferred ? newDefer : this, [ returned ] );
 									}
@@ -74,9 +70,15 @@ jQuery.extend({
 					return obj;
 				}
 			},
-			deferred = promise.promise({}),
+			deferred,
 			key;
 
+		// Keep pipe for back-compat
+		promise.pipe = promise.then;
+
+		// Construct deferred
+		deferred = promise.promise({});
+
 		for ( key in lists ) {
 			deferred[ key ] = lists[ key ].fire;
 			deferred[ key + "With" ] = lists[ key ].fireWith;
@@ -127,7 +129,7 @@ jQuery.extend({
 		if ( length > 1 ) {
 			for ( ; i < length; i++ ) {
 				if ( args[ i ] && args[ i ].promise && jQuery.isFunction( args[ i ].promise ) ) {
-					args[ i ].promise().then( resolveFunc(i), deferred.reject, progressFunc(i) );
+					args[ i ].promise().done( resolveFunc(i) ).fail( deferred.reject ).progress( progressFunc(i) );
 				} else {
 					--count;
 				}

test/unit/deferred.js

@@ -8,32 +8,36 @@ jQuery.each( [ "", " - new operator" ], function( _, withNew ) {
 
 	test("jQuery.Deferred" + withNew, function() {
 
-		expect( 22 );
+		expect( 23 );
 
-		createDeferred().resolve().then( function() {
+		var defer = createDeferred();
+
+		strictEqual( defer.pipe, defer.then, "pipe is an alias of then" );
+
+		createDeferred().resolve().done(function() {
 			ok( true , "Success on resolve" );
 			ok( this.isResolved(), "Deferred is resolved" );
 			strictEqual( this.state(), "resolved", "Deferred is resolved (state)" );
-		}, function() {
+		}).fail(function() {
 			ok( false , "Error on resolve" );
-		}).always( function() {
+		}).always(function() {
 			ok( true , "Always callback on resolve" );
 		});
 
-		createDeferred().reject().then( function() {
+		createDeferred().reject().done(function() {
 			ok( false , "Success on reject" );
-		}, function() {
+		}).fail(function() {
 			ok( true , "Error on reject" );
 			ok( this.isRejected(), "Deferred is rejected" );
 			strictEqual( this.state(), "rejected", "Deferred is rejected (state)" );
-		}).always( function() {
+		}).always(function() {
 			ok( true , "Always callback on reject" );
 		});
 
-		createDeferred( function( defer ) {
+		createDeferred(function( defer ) {
 			ok( this === defer , "Defer passed as this & first argument" );
 			this.resolve( "done" );
-		}).then( function( value ) {
+		}).done( function( value ) {
 			strictEqual( value , "done" , "Passed function executed" );
 		});
 
@@ -58,7 +62,7 @@ jQuery.each( [ "", " - new operator" ], function( _, withNew ) {
 
 test( "jQuery.Deferred - chainability", function() {
 
-	var methods = "resolve reject notify resolveWith rejectWith notifyWith done fail progress then always".split( " " ),
+	var methods = "resolve reject notify resolveWith rejectWith notifyWith done fail progress always".split( " " ),
 		defer = jQuery.Deferred();
 
 	expect( methods.length );
@@ -69,12 +73,12 @@ test( "jQuery.Deferred - chainability", function() {
 	});
 });
 
-test( "jQuery.Deferred.pipe - filtering (done)", function() {
+test( "jQuery.Deferred.then - filtering (done)", function() {
 
 	expect(4);
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe(function( a, b ) {
+		piped = defer.then(function( a, b ) {
 			return a * b;
 		}),
 		value1,
@@ -96,21 +100,21 @@ test( "jQuery.Deferred.pipe - filtering (done)", function() {
 	strictEqual( value2, 3, "second resolve value ok" );
 	strictEqual( value3, 6, "result of filter ok" );
 
-	jQuery.Deferred().reject().pipe(function() {
-		ok( false, "pipe should not be called on reject" );
+	jQuery.Deferred().reject().then(function() {
+		ok( false, "then should not be called on reject" );
 	});
 
-	jQuery.Deferred().resolve().pipe( jQuery.noop ).done(function( value ) {
-		strictEqual( value, undefined, "pipe done callback can return undefined/null" );
+	jQuery.Deferred().resolve().then( jQuery.noop ).done(function( value ) {
+		strictEqual( value, undefined, "then done callback can return undefined/null" );
 	});
 });
 
-test( "jQuery.Deferred.pipe - filtering (fail)", function() {
+test( "jQuery.Deferred.then - filtering (fail)", function() {
 
 	expect(4);
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe( null, function( a, b ) {
+		piped = defer.then( null, function( a, b ) {
 			return a * b;
 		} ),
 		value1,
@@ -132,21 +136,21 @@ test( "jQuery.Deferred.pipe - filtering (fail)", function() {
 	strictEqual( value2, 3, "second reject value ok" );
 	strictEqual( value3, 6, "result of filter ok" );
 
-	jQuery.Deferred().resolve().pipe( null, function() {
-		ok( false, "pipe should not be called on resolve" );
+	jQuery.Deferred().resolve().then( null, function() {
+		ok( false, "then should not be called on resolve" );
 	} );
 
-	jQuery.Deferred().reject().pipe( null, jQuery.noop ).fail(function( value ) {
-		strictEqual( value, undefined, "pipe fail callback can return undefined/null" );
+	jQuery.Deferred().reject().then( null, jQuery.noop ).fail(function( value ) {
+		strictEqual( value, undefined, "then fail callback can return undefined/null" );
 	});
 });
 
-test( "jQuery.Deferred.pipe - filtering (progress)", function() {
+test( "jQuery.Deferred.then - filtering (progress)", function() {
 
 	expect(3);
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe( null, null, function( a, b ) {
+		piped = defer.then( null, null, function( a, b ) {
 			return a * b;
 		} ),
 		value1,
@@ -169,12 +173,12 @@ test( "jQuery.Deferred.pipe - filtering (progress)", function() {
 	strictEqual( value3, 6, "result of filter ok" );
 });
 
-test( "jQuery.Deferred.pipe - deferred (done)", function() {
+test( "jQuery.Deferred.then - deferred (done)", function() {
 
 	expect(3);
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe(function( a, b ) {
+		piped = defer.then(function( a, b ) {
 			return jQuery.Deferred(function( defer ) {
 				defer.reject( a * b );
 			});
@@ -199,12 +203,12 @@ test( "jQuery.Deferred.pipe - deferred (done)", function() {
 	strictEqual( value3, 6, "result of filter ok" );
 });
 
-test( "jQuery.Deferred.pipe - deferred (fail)", function() {
+test( "jQuery.Deferred.then - deferred (fail)", function() {
 
 	expect(3);
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe( null, function( a, b ) {
+		piped = defer.then( null, function( a, b ) {
 			return jQuery.Deferred(function( defer ) {
 				defer.resolve( a * b );
 			});
@@ -229,12 +233,12 @@ test( "jQuery.Deferred.pipe - deferred (fail)", function() {
 	strictEqual( value3, 6, "result of filter ok" );
 });
 
-test( "jQuery.Deferred.pipe - deferred (progress)", function() {
+test( "jQuery.Deferred.then - deferred (progress)", function() {
 
 	expect(3);
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe( null, null, function( a, b ) {
+		piped = defer.then( null, null, function( a, b ) {
 			return jQuery.Deferred(function( defer ) {
 				defer.resolve( a * b );
 			});
@@ -259,13 +263,13 @@ test( "jQuery.Deferred.pipe - deferred (progress)", function() {
 	strictEqual( value3, 6, "result of filter ok" );
 });
 
-test( "jQuery.Deferred.pipe - context", function() {
+test( "jQuery.Deferred.then - context", function() {
 
 	expect(4);
 
 	var context = {};
 
-	jQuery.Deferred().resolveWith( context, [ 2 ] ).pipe(function( value ) {
+	jQuery.Deferred().resolveWith( context, [ 2 ] ).then(function( value ) {
 		return value * 3;
 	}).done(function( value ) {
 		strictEqual( this, context, "custom context correctly propagated" );
@@ -273,7 +277,7 @@ test( "jQuery.Deferred.pipe - context", function() {
 	});
 
 	var defer = jQuery.Deferred(),
-		piped = defer.pipe(function( value ) {
+		piped = defer.then(function( value ) {
 			return value * 3;
 		});