Build: Auto-convert sources to AMD

jQuery source has been migrated in gh-4541 from AMD to ES modules. To maintain
support for consumers of our AMD modules, this commits adds a task transpiling
the ES modules sources in `src/` to AMD in `amd/`.

A "Load with AMD" checkbox was also restored to the QUnit setup. Note that,
contrary to jQuery 3.x, AMD files need to be generated via `grunt amd` or
`grunt` as sources are not authored in ECMAScript modules. To achieve a similar
no-compile experience during jQuery 4.x testing, use the new "Load as modules"
checkbox which works in all supported browsers except for IE & Edge (the
legacy, EdgeHTML-based one).

Ref gh-4541
Closes gh-4554

.eslintignore

@@ -1,4 +1,4 @@
-external
+amd
 node_modules
 *.min.js
 dist/**

.gitignore

@@ -16,6 +16,8 @@ npm-debug.log*
 /dist/*
 !/dist/.eslintrc.json
 
+/amd
+
 /node_modules
 
 /test/data/core/jquery-iterability-transpiled.js

Gruntfile.js

@@ -178,6 +178,7 @@ module.exports = function( grunt ) {
 
 					{ pattern: "dist/jquery.*", included: false, served: true },
 					{ pattern: "src/**", type: "module", included: false, served: true },
+					{ pattern: "amd/**", included: false, served: true },
 					{ pattern: "node_modules/**", included: false, served: true },
 					{
 						pattern: "test/**/*.@(js|css|jpg|html|xml|svg)",
@@ -319,6 +320,7 @@ module.exports = function( grunt ) {
 	grunt.registerTask( "default", [
 		"eslint:dev",
 		"build:*:*",
+		"amd",
 		"uglify",
 		"remove_map_comment",
 		"dist:*",

build/release.js

@@ -22,18 +22,23 @@ module.exports = function( Release ) {
 
 		npmTags = Release.npmTags;
 
+	function setSrcVersion( filepath ) {
+		var contents = fs.readFileSync( filepath, "utf8" );
+		contents = contents.replace( /@VERSION/g, Release.newVersion );
+		fs.writeFileSync( filepath, contents, "utf8" );
+	}
+
 	Release.define( {
 		npmPublish: true,
 		issueTracker: "github",
 
 		/**
-		 * Set the version in the src folder for distributing AMD
+		 * Set the version in the src folder for distributing ES modules
+		 * and in the amd folder for AMD.
 		 */
 		_setSrcVersion: function() {
-			var corePath = __dirname + "/../src/core.js",
-				contents = fs.readFileSync( corePath, "utf8" );
-			contents = contents.replace( /@VERSION/g, Release.newVersion );
-			fs.writeFileSync( corePath, contents, "utf8" );
+			setSrcVersion( `${ __dirname }/../src/core.js` );
+			setSrcVersion( `${ __dirname }/../amd/core.js` );
 		},
 
 		/**

build/release/dist.js

@@ -13,6 +13,7 @@ module.exports = function( Release, files, complete ) {
 
 		// These files are included with the distribution
 		extras = [
+			"amd",
 			"src",
 			"LICENSE.txt",
 			"AUTHORS.txt",

build/tasks/amd.js

@@ -0,0 +1,43 @@
+/**
+ * Compiles sources from ES Modules in `src/` to AMD in `amd/`.
+ */
+
+"use strict";
+
+module.exports = function( grunt ) {
+	const path = require( "path" );
+	const rimraf = require( "rimraf" );
+	const rollup = require( "rollup" );
+	const srcFolder = path.resolve( __dirname, "..", "..", "src" );
+	const amdFolder = path.resolve( srcFolder, "..", "amd" );
+	const inputFileName = "jquery.js";
+
+	const inputRollupOptions = {
+		input: path.resolve( srcFolder, inputFileName ),
+		preserveModules: true
+	};
+
+	const outputRollupOptions = {
+		format: "amd",
+		dir: "amd"
+	};
+
+	grunt.registerTask(
+		"amd",
+		"Convert ES modules from `src/` to AMD modules in `amd/`",
+		async function() {
+			const done = this.async();
+
+			try {
+				grunt.verbose.writeln( "Removing the 'amd' directory..." );
+				rimraf( amdFolder, async function() {
+					const bundle = await rollup.rollup( inputRollupOptions );
+					await bundle.write( outputRollupOptions );
+					grunt.log.ok( "Sources from 'src' converted to AMD in 'amd'." );
+					done();
+				} );
+			} catch ( err ) {
+				done( err );
+			}
+		} );
+};

package.json

@@ -60,7 +60,8 @@
     "qunit": "2.9.2",
     "raw-body": "2.3.3",
     "requirejs": "2.3.6",
-    "rollup": "1.25.2",
+    "rimraf": "3.0.0",
+    "rollup": "1.27.6",
     "sinon": "7.3.1",
     "strip-json-comments": "2.0.1",
     "testswarm": "1.1.0",

test/data/testinit.js

@@ -299,14 +299,16 @@ QUnit.testUnlessIE = QUnit.isIE ? QUnit.skip : QUnit.test;
 
 this.loadTests = function() {
 
-	// Directly load tests that need synchronous evaluation
-	if ( !QUnit.urlParams.esmodules || document.readyState === "loading" ) {
+	// QUnit.config is populated from QUnit.urlParams but only at the beginning
+	// of the test run. We need to read both.
+	var amd = QUnit.config.amd || QUnit.urlParams.amd;
+
+	// Directly load tests that need evaluation before DOMContentLoaded.
+	if ( !amd || document.readyState === "loading" ) {
 		document.write( "<script src='" + parentUrl + "test/unit/ready.js'><\x2Fscript>" );
 	} else {
 		QUnit.module( "ready", function() {
-			QUnit.test( "jQuery ready", function( assert ) {
-				assert.ok( false, "Test should be initialized before DOM ready" );
-			} );
+			QUnit.skip( "jQuery ready tests skipped in async mode", function() {} );
 		} );
 	}
 

test/index.html

@@ -19,7 +19,7 @@
 	<!-- See testinit for the list of tests -->
 	<script src="data/testinit.js"></script>
 
-	<!-- A script that includes jQuery min, dev, or ES modules -->
+	<!-- A script that includes jQuery min, dev, ES modules or AMD -->
 	<!-- Adds "basic" URL option, even to iframes -->
 	<!-- iframes will not load AMD as loading needs to be synchronous for some tests -->
 	<!-- Also executes the function above to load tests -->
@@ -29,7 +29,7 @@
 		// Load tests if they have not been loaded
 		// This is in a different script tag to ensure that
 		// jQuery is on the page when the testrunner executes
-		if ( !QUnit.urlParams.esmodules ) {
+		if ( !QUnit.urlParams.esmodules && !QUnit.urlParams.amd ) {
 			loadTests();
 		}
 	</script>

test/jquery.js

@@ -28,7 +28,12 @@
 			QUnit.config.urlConfig.push( {
 				id: "esmodules",
 				label: "Load as modules",
-				tooltip: "Load a relevant jQuery module file (and its dependencies)"
+				tooltip: "Load the jQuery module file (and its dependencies)"
+			} );
+			QUnit.config.urlConfig.push( {
+				id: "amd",
+				label: "Load with AMD",
+				tooltip: "Load the AMD jQuery file (and its dependencies)"
 			} );
 		}
 
@@ -39,7 +44,7 @@
 		} );
 	}
 
-	// Honor AMD loading on the main window (detected by seeing QUnit on it).
+	// Honor ES modules loading on the main window (detected by seeing QUnit on it).
 	// This doesn't apply to iframes because they synchronously expect jQuery to be there.
 	if ( urlParams.esmodules && window.QUnit ) {
 
@@ -57,6 +62,20 @@
 
 		eval( dynamicImportSource );
 
+	// Apply similar treatment for AMD modules
+	} else if ( urlParams.amd && window.QUnit ) {
+		require.config( {
+			baseUrl: parentUrl
+		} );
+		src = "amd/jquery";
+
+		// Include tests if specified
+		if ( typeof loadTests !== "undefined" ) {
+			require( [ src ], loadTests );
+		} else {
+			require( [ src ] );
+		}
+
 	// Otherwise, load synchronously
 	} else {
 		document.write( "<script id='jquery-js' nonce='jquery+hardcoded+nonce' src='" + parentUrl + src + "'><\x2Fscript>" );