Core: implement ready without Deferred

- Make jQuery.ready promise-compatible
- Gives up sync guarantee for post-ready callbacks

Fixes gh-1778
Fixes gh-1823
Close gh-2891

Gruntfile.js

@@ -63,6 +63,10 @@ module.exports = function( grunt ) {
 					callbacks: [ "deferred" ],
 					css: [ "effects", "dimensions", "offset" ],
 					"css/showHide": [ "effects" ],
+					deferred: {
+						remove: [ "ajax", "effects", "queue", "core/ready" ],
+						include: [ "core/ready-no-deferred" ]
+					},
 					sizzle: [ "css/hiddenVisibleSelectors", "effects/animatedSelector" ]
 				}
 			}

build/tasks/build.js

@@ -168,7 +168,8 @@ module.exports = function( grunt ) {
 			 *  whether it should included or excluded
 			 */
 			excluder = function( flag ) {
-				var m = /^(\+|\-|)([\w\/-]+)$/.exec( flag ),
+				var additional,
+					m = /^(\+|\-|)([\w\/-]+)$/.exec( flag ),
 					exclude = m[ 1 ] === "-",
 					module = m[ 2 ];
 
@@ -192,8 +193,16 @@ module.exports = function( grunt ) {
 							}
 						}
 
+						additional = removeWith[ module ];
+
 						// Check removeWith list
-						excludeList( removeWith[ module ] );
+						if ( additional ) {
+							excludeList( additional.remove || additional );
+							if ( additional.include ) {
+								included = included.concat( additional.include );
+								grunt.log.writeln( "+" + additional.include );
+							}
+						}
 					} else {
 						grunt.log.error( "Module \"" + module + "\" is a minimum requirement." );
 						if ( module === "selector" ) {

src/core/ready-no-deferred.js

@@ -0,0 +1,109 @@
+define( [
+	"../core",
+	"../var/document"
+], function( jQuery, document ) {
+
+var readyCallbacks = [],
+	readyFiring = false,
+	whenReady = function( fn ) {
+		readyCallbacks.push( fn );
+	},
+	executeReady = function( fn ) {
+
+		// Prevent errors from freezing future callback execution (gh-1823)
+		// Not backwards-compatible as this does not execute sync
+		window.setTimeout( function() {
+			fn.call( document, jQuery );
+		} );
+	};
+
+jQuery.fn.ready = function( fn ) {
+	whenReady( fn );
+	return this;
+};
+
+jQuery.extend( {
+
+	// Is the DOM ready to be used? Set to true once it occurs.
+	isReady: false,
+
+	// A counter to track how many items to wait for before
+	// the ready event fires. See #6781
+	readyWait: 1,
+
+	// Hold (or release) the ready event
+	holdReady: function( hold ) {
+		if ( hold ) {
+			jQuery.readyWait++;
+		} else {
+			jQuery.ready( true );
+		}
+	},
+
+	ready: function( wait ) {
+
+		// Abort if there are pending holds or we're already ready
+		if ( wait === true ? --jQuery.readyWait : jQuery.isReady ) {
+			return;
+		}
+
+		// Remember that the DOM is ready
+		jQuery.isReady = true;
+
+		// If a normal DOM Ready event fired, decrement, and wait if need be
+		if ( wait !== true && --jQuery.readyWait > 0 ) {
+			return;
+		}
+
+		whenReady = function( fn ) {
+			readyCallbacks.push( fn );
+
+			if ( !readyFiring ) {
+				readyFiring = true;
+
+				while ( readyCallbacks.length ) {
+					fn = readyCallbacks.shift();
+					if ( jQuery.isFunction( fn ) ) {
+						executeReady( fn );
+					}
+				}
+				readyFiring = false;
+			}
+		};
+
+		whenReady();
+	}
+} );
+
+// Make jQuery.ready Promise consumable (gh-1778)
+jQuery.ready.then = jQuery.fn.ready;
+
+/**
+ * The ready event handler and self cleanup method
+ */
+function completed() {
+	document.removeEventListener( "DOMContentLoaded", completed );
+	window.removeEventListener( "load", completed );
+	jQuery.ready();
+}
+
+// Catch cases where $(document).ready() is called
+// after the browser event has already occurred.
+// Support: IE9-10 only
+// Older IE sometimes signals "interactive" too soon
+if ( document.readyState === "complete" ||
+	( document.readyState !== "loading" && !document.documentElement.doScroll ) ) {
+
+	// Handle it asynchronously to allow scripts the opportunity to delay ready
+	window.setTimeout( jQuery.ready );
+
+} else {
+
+	// Use the handy event callback
+	document.addEventListener( "DOMContentLoaded", completed );
+
+	// A fallback to window.onload, that will always work
+	window.addEventListener( "load", completed );
+}
+
+} );

src/core/ready.js

@@ -5,12 +5,11 @@ define( [
 ], function( jQuery, document ) {
 
 // The deferred used on DOM ready
-var readyList;
+var readyList = jQuery.Deferred();
 
 jQuery.fn.ready = function( fn ) {
 
-	// Add the callback
-	jQuery.ready.promise().done( fn );
+	readyList.then( fn );
 
 	return this;
 };
@@ -54,43 +53,32 @@ jQuery.extend( {
 	}
 } );
 
-/**
- * The ready event handler and self cleanup method
- */
+jQuery.ready.then = readyList.then;
+
+// The ready event handler and self cleanup method
 function completed() {
 	document.removeEventListener( "DOMContentLoaded", completed );
 	window.removeEventListener( "load", completed );
 	jQuery.ready();
 }
 
-jQuery.ready.promise = function( obj ) {
-	if ( !readyList ) {
+// Catch cases where $(document).ready() is called
+// after the browser event has already occurred.
+// Support: IE <=9 - 10 only
+// Older IE sometimes signals "interactive" too soon
+if ( document.readyState === "complete" ||
+	( document.readyState !== "loading" && !document.documentElement.doScroll ) ) {
 
-		readyList = jQuery.Deferred();
+	// Handle it asynchronously to allow scripts the opportunity to delay ready
+	window.setTimeout( jQuery.ready );
 
-		// Catch cases where $(document).ready() is called
-		// after the browser event has already occurred.
-		// Support: IE <=9 - 10 only
-		// Older IE sometimes signals "interactive" too soon
-		if ( document.readyState === "complete" ||
-			( document.readyState !== "loading" && !document.documentElement.doScroll ) ) {
+} else {
 
-			// Handle it asynchronously to allow scripts the opportunity to delay ready
-			window.setTimeout( jQuery.ready );
+	// Use the handy event callback
+	document.addEventListener( "DOMContentLoaded", completed );
 
-		} else {
-
-			// Use the handy event callback
-			document.addEventListener( "DOMContentLoaded", completed );
-
-			// A fallback to window.onload, that will always work
-			window.addEventListener( "load", completed );
-		}
-	}
-	return readyList.promise( obj );
-};
-
-// Kick off the DOM ready check even if the user does not
-jQuery.ready.promise();
+	// A fallback to window.onload, that will always work
+	window.addEventListener( "load", completed );
+}
 
 } );

test/unit/ready.js

@@ -2,6 +2,7 @@ QUnit.module( "ready" );
 
 ( function() {
 	var notYetReady, noEarlyExecution,
+		promisified = Promise.resolve( jQuery.ready ),
 		order = [],
 		args = {};
 
@@ -26,13 +27,36 @@ QUnit.module( "ready" );
 		};
 	}
 
+	function throwError( num ) {
+
+		// Not a global QUnit failure
+		var onerror = window.onerror;
+		window.onerror = function() {
+			window.onerror = onerror;
+		};
+
+		throw new Error( "Ready error " + num );
+	}
+
 	// Bind to the ready event in every possible way.
 	jQuery( makeHandler( "a" ) );
 	jQuery( document ).ready( makeHandler( "b" ) );
 
+	// Throw in an error to ensure other callbacks are called
+	jQuery( function() {
+		throwError( 1 );
+	} );
+
+	// Throw two errors in a row
+	jQuery( function() {
+		throwError( 2 );
+	} );
+	jQuery.when( jQuery.ready ).done( makeHandler( "c" ) );
+
 	// Do it twice, just to be sure.
-	jQuery( makeHandler( "c" ) );
-	jQuery( document ).ready( makeHandler( "d" ) );
+	jQuery( makeHandler( "d" ) );
+	jQuery( document ).ready( makeHandler( "e" ) );
+	jQuery.when( jQuery.ready ).done( makeHandler( "f" ) );
 
 	noEarlyExecution = order.length === 0;
 
@@ -44,7 +68,7 @@ QUnit.module( "ready" );
 			"Handlers bound to DOM ready should not execute before DOM ready" );
 
 		// Ensure execution order.
-		assert.deepEqual( order, [ "a", "b", "c", "d" ],
+		assert.deepEqual( order, [ "a", "b", "c", "d", "e", "f" ],
 			"Bound DOM ready handlers should execute in on-order" );
 
 		// Ensure handler argument is correct.
@@ -55,16 +79,48 @@ QUnit.module( "ready" );
 
 		order = [];
 
-		// Now that the ready event has fired, again bind to the ready event
-		// in every possible way. These event handlers should execute immediately.
+		// Now that the ready event has fired, again bind to the ready event.
+		// These ready handlers should execute asynchronously.
+		var done = assert.async();
 		jQuery( makeHandler( "g" ) );
-		assert.equal( order.pop(), "g", "Event handler should execute immediately" );
-		assert.equal( args.g, jQuery, "Argument passed to fn in jQuery( fn ) should be jQuery" );
-
 		jQuery( document ).ready( makeHandler( "h" ) );
-		assert.equal( order.pop(), "h", "Event handler should execute immediately" );
-		assert.equal( args.h, jQuery,
-			"Argument passed to fn in jQuery(document).ready( fn ) should be jQuery" );
+		window.setTimeout( function() {
+			assert.equal( order.shift(), "g", "Event handler should execute immediately, but async" );
+			assert.equal( args.g, jQuery, "Argument passed to fn in jQuery( fn ) should be jQuery" );
+
+			assert.equal( order.shift(), "h", "Event handler should execute immediately, but async" );
+			assert.equal( args.h, jQuery,
+				"Argument passed to fn in jQuery(document).ready( fn ) should be jQuery" );
+			done();
+		} );
 	} );
 
+	QUnit.test( "Promise.resolve(jQuery.ready)", function( assert ) {
+		assert.expect( 2 );
+		var done = jQuery.map( new Array( 2 ), function() { return assert.async(); } );
+
+		promisified.then( function() {
+			assert.ok( jQuery.isReady, "Native promised resolved" );
+			done.pop()();
+		} );
+
+		Promise.resolve( jQuery.ready ).then( function() {
+			assert.ok( jQuery.isReady, "Native promised resolved" );
+			done.pop()();
+		} );
+	} );
+
+	QUnit.test( "Error in ready callback does not halt all future executions (gh-1823)", function( assert ) {
+		assert.expect( 1 );
+		var done = assert.async();
+
+		jQuery( function() {
+			throwError( 3 );
+		} );
+
+		jQuery( function() {
+			assert.ok( true, "Subsequent handler called" );
+			done();
+		} );
+	} );
 } )();