Fixing $.proxy to work like (and use) Function.prototype.bind (ticket #7783)

http://bugs.jquery.com/ticket/7783

src/core.js

@@ -740,31 +740,42 @@ jQuery.extend({
 	// A global GUID counter for objects
 	guid: 1,
 
-	proxy: function( fn, proxy, thisObject ) {
-		if ( arguments.length === 2 ) {
-			if ( typeof proxy === "string" ) {
-				thisObject = fn;
-				fn = thisObject[ proxy ];
-				proxy = undefined;
-
-			} else if ( proxy && !jQuery.isFunction( proxy ) ) {
-				thisObject = proxy;
-				proxy = undefined;
-			}
+	// Bind a function to a context, optionally partially applying any
+	// arguments.
+	proxy: function( fn, context ) {
+		var args, proxy;
+
+		// Quick check to determine if target is callable, in the spec
+		// this throws a TypeError, but we will just return undefined.
+		if ( ! jQuery.isFunction( fn ) ) {
+			return undefined;
 		}
 
-		if ( !proxy && fn ) {
-			proxy = function() {
-				return fn.apply( thisObject || this, arguments );
-			};
+		if ( jQuery.isFunction( Function.prototype.bind ) ) {
+			// Native bind
+			args = slice.call( arguments, 1 );
+			proxy = Function.prototype.bind.apply( fn, args );
+		} else {
+			// Simulated bind
+			args = slice.call( arguments, 2 );
+			if ( args.length ) {
+				proxy = function() {
+					return arguments.length ?
+						fn.apply( context, args.concat( slice.call( arguments ) ) ) :
+						fn.apply( context, args );
+				};
+			} else {
+				proxy = function() {
+					return arguments.length ?
+						fn.apply( context, arguments ) :
+						fn.call( context );
+				};
+			}
 		}
 
 		// Set the guid of unique handler to the same of original handler, so it can be removed
-		if ( fn ) {
-			proxy.guid = fn.guid = fn.guid || proxy.guid || jQuery.guid++;
-		}
+		proxy.guid = fn.guid = fn.guid || proxy.guid || jQuery.guid++;
 
-		// So proxy can be declared as an argument
 		return proxy;
 	},
 

src/event.js

@@ -891,6 +891,8 @@ if ( document.addEventListener ) {
 
 jQuery.each(["bind", "one"], function( i, name ) {
 	jQuery.fn[ name ] = function( type, data, fn ) {
+		var handler;
+
 		// Handle object literals
 		if ( typeof type === "object" ) {
 			for ( var key in type ) {
@@ -904,10 +906,15 @@ jQuery.each(["bind", "one"], function( i, name ) {
 			data = undefined;
 		}
 
-		var handler = name === "one" ? jQuery.proxy( fn, function( event ) {
-			jQuery( this ).unbind( event, handler );
-			return fn.apply( this, arguments );
-		}) : fn;
+		if ( name === "one" ) {
+			handler = function( event ) {
+				jQuery( this ).unbind( event, handler );
+				return fn.apply( this, arguments );
+			};
+			handler.guid = fn.guid || jQuery.guid++;
+		} else {
+			handler = fn;
+		}
 
 		if ( type === "unload" && name !== "one" ) {
 			this.one( type, data, fn );
@@ -971,24 +978,27 @@ jQuery.fn.extend({
 	toggle: function( fn ) {
 		// Save reference to arguments for access in closure
 		var args = arguments,
-			i = 1;
+			guid = fn.guid || jQuery.guid++,
+			i = 0,
+			toggler = function( event ) {
+				// Figure out which function to execute
+				var lastToggle = ( jQuery.data( this, "lastToggle" + fn.guid ) || 0 ) % i;
+				jQuery.data( this, "lastToggle" + fn.guid, lastToggle + 1 );
+
+				// Make sure that clicks stop
+				event.preventDefault();
+
+				// and execute the function
+				return args[ lastToggle ].apply( this, arguments ) || false;
+			};
 
 		// link all the functions, so any of them can unbind this click handler
+		toggler.guid = guid;
 		while ( i < args.length ) {
-			jQuery.proxy( fn, args[ i++ ] );
+			args[ i++ ].guid = guid;
 		}
 
-		return this.click( jQuery.proxy( fn, function( event ) {
-			// Figure out which function to execute
-			var lastToggle = ( jQuery.data( this, "lastToggle" + fn.guid ) || 0 ) % i;
-			jQuery.data( this, "lastToggle" + fn.guid, lastToggle + 1 );
-
-			// Make sure that clicks stop
-			event.preventDefault();
-
-			// and execute the function
-			return args[ lastToggle ].apply( this, arguments ) || false;
-		}));
+		return this.click( toggler );
 	},
 
 	hover: function( fnOver, fnOut ) {

test/unit/core.js

@@ -858,7 +858,7 @@ test("jQuery.isEmptyObject", function(){
 });
 
 test("jQuery.proxy", function(){
-	expect(4);
+	expect(5);
 
 	var test = function(){ equals( this, thisObject, "Make sure that scope is set properly." ); };
 	var thisObject = { foo: "bar", method: test };
@@ -872,8 +872,13 @@ test("jQuery.proxy", function(){
 	// Make sure it doesn't freak out
 	equals( jQuery.proxy( null, thisObject ), undefined, "Make sure no function was returned." );
 
-	// Use the string shortcut
-	jQuery.proxy( thisObject, "method" )();
+        // Partial application
+        var test2 = function( a ){ equals( a, "pre-applied", "Ensure arguments can be pre-applied." ); };
+        jQuery.proxy( test2, null, "pre-applied" )();
+
+        // Partial application w/ normal arguments
+        var test3 = function( a, b ){ equals( b, "normal", "Ensure arguments can be pre-applied and passed as usual." ); };
+        jQuery.proxy( test3, null, "pre-applied" )( "normal" );
 });
 
 test("jQuery.parseJSON", function(){