Build: Add native ESM distribution

Gruntfile.js

@@ -27,6 +27,18 @@ module.exports = function (grunt) {
       'src-css': {
         src: 'src/core/qunit.css',
         dest: 'qunit/qunit.css'
+      },
+      'src-export-cjs-wrappers': {
+        src: 'src/core/qunit-wrapper-bundler-require.js',
+        expand: true,
+        flatten: true,
+        dest: 'qunit/'
+      },
+      'src-export-esm-wrappers': {
+        src: 'src/core/qunit-wrapper-nodejs-module.js',
+        expand: true,
+        flatten: true,
+        dest: 'qunit/esm/'
       }
     },
     search: {

package.json

@@ -37,6 +37,20 @@
     "LICENSE.txt"
   ],
   "main": "qunit/qunit.js",
+  "exports": {
+    ".": {
+      "node": {
+        "import": "./qunit/esm/qunit-wrapper-nodejs-module.js",
+        "default": "./qunit/qunit.js"
+      },
+      "module": {
+        "import": "./qunit/esm/qunit.module.js",
+        "default": "./qunit/qunit-wrapper-bundler-require.js"
+      },
+      "import": "./qunit/esm/qunit.module.js",
+      "default": "./qunit/qunit.js"
+    }
+  },
   "engines": {
     "node": ">=18"
   },
@@ -82,8 +96,8 @@
     "tap-min": "^3.0.0"
   },
   "scripts": {
-    "build": "rollup -c && grunt copy:src-css",
-    "build-coverage": "rollup -c --environment BUILD_TARGET:coverage && grunt copy:src-css",
+    "build": "rollup -c && grunt copy",
+    "build-coverage": "rollup -c --environment BUILD_TARGET:coverage && grunt copy",
     "build-dev": "node build/dev.js",
     "benchmark": "npm install --silent --no-audit --prefix test/benchmark/ && node test/benchmark/micro.js",
     "lint": "eslint --cache .",

rollup.config.js

@@ -8,44 +8,74 @@ const replace = require('@rollup/plugin-replace');
 const { replacements } = require('./build/dist-replace.js');
 const isCoverage = process.env.BUILD_TARGET === 'coverage';
 
-module.exports = {
-  input: 'src/core/qunit.js',
-  output: {
-    file: 'qunit/qunit.js',
-    sourcemap: isCoverage,
-    format: 'iife',
-    exports: 'none',
+const banner = `/*!
+ * QUnit @VERSION
+ * https://qunitjs.com/
+ *
+ * Copyright OpenJS Foundation and other contributors
+ * Released under the MIT license
+ * https://jquery.org/license
+ */`;
 
-    // eslint-disable-next-line no-multi-str
-    banner: '/*!\n\
- * QUnit @VERSION\n\
- * https://qunitjs.com/\n\
- *\n\
- * Copyright OpenJS Foundation and other contributors\n\
- * Released under the MIT license\n\
- * https://jquery.org/license\n\
- */'
-  },
-  plugins: [
-    replace({
-      preventAssignment: true,
-      delimiters: ['', ''],
-      ...replacements
-    }),
-    nodeResolve(),
-    commonjs(),
-    babel({
-      babelHelpers: 'bundled',
-      babelrc: false,
-      presets: [
-        ['@babel/preset-env', {
-          targets: {
-            ie: 11,
-            safari: 7,
-            node: 18
-          }
-        }]
-      ]
-    })
-  ]
+const replacementOptions = {
+  preventAssignment: true,
+  delimiters: ['', ''],
+  ...replacements
 };
+
+module.exports = [
+  {
+    input: 'src/core/qunit-commonjs.js',
+    output: {
+      file: 'qunit/qunit.js',
+      sourcemap: isCoverage,
+      format: 'iife',
+      exports: 'none',
+      banner: banner
+    },
+    plugins: [
+      replace(replacementOptions),
+      nodeResolve(),
+      commonjs(),
+      babel({
+        babelHelpers: 'bundled',
+        babelrc: false,
+        presets: [
+          ['@babel/preset-env', {
+            targets: {
+              ie: 11,
+              safari: 7,
+              node: 18
+            }
+          }]
+        ]
+      })
+    ]
+  },
+  {
+    input: 'src/core/qunit.js',
+    output: {
+      file: 'qunit/esm/qunit.module.js',
+      format: 'es',
+      exports: 'named',
+      banner: banner
+    },
+    plugins: [
+      replace(replacementOptions),
+      nodeResolve(),
+      commonjs(),
+      babel({
+        babelHelpers: 'bundled',
+        babelrc: false,
+        presets: [
+          ['@babel/preset-env', {
+            targets: {
+              safari: 10,
+              node: 18
+            }
+          }]
+        ]
+      })
+    ]
+  }
+];

src/core/qunit-commonjs.js

@@ -0,0 +1,12 @@
+/* global module, exports */
+import QUnit from './qunit.js';
+
+// For Node.js
+if (typeof module !== 'undefined' && module && module.exports) {
+  module.exports = QUnit;
+}
+
+// For CommonJS with exports, but without module.exports, like Rhino
+if (typeof exports !== 'undefined' && exports) {
+  exports.QUnit = QUnit;
+}

src/core/qunit-wrapper-bundler-require.js

@@ -0,0 +1,9 @@
+/* eslint-env node */
+
+// In a single bundler invocation, if different parts or dependencies
+// of a project mix ESM and CJS, avoid a split-brain state by making
+// sure both import and re-use the same instance via this wrapper.
+//
+// Bundlers generally allow requiring an ESM file from CommonJS.
+const { QUnit } = require('./esm/qunit.module.js');
+module.exports = QUnit;

src/core/qunit-wrapper-nodejs-module.js

@@ -0,0 +1,42 @@
+// In a single Node.js process, if different parts or dependencies
+// of a project mix ESM and CJS, avoid a split-brain state by making
+// sure both import and re-use the same instance via this wrapper.
+//
+// Node.js 18+ can import a CommonJS file from ESM.
+import QUnit from '../qunit.js';
+
+export const {
+  assert,
+  begin,
+  config,
+  diff,
+  done,
+  dump,
+  equiv,
+  hooks,
+  is,
+  isLocal,
+  log,
+  module,
+  moduleDone,
+  moduleStart,
+  objectType,
+  on,
+  only,
+  onUncaughtException,
+  pushFailure,
+  reporters,
+  skip,
+  stack,
+  start,
+  test,
+  testDone,
+  testStart,
+  todo,
+  urlParams,
+  version
+} = QUnit;
+
+export { QUnit };
+
+export default QUnit;

src/core/qunit.js

@@ -6,7 +6,7 @@ import diff from './diff.js';
 import dump from './dump.js';
 import equiv from './equiv.js';
 import { on } from './events.js';
-import { window, document } from './globals.js';
+import { globalThis, window, document } from './globals.js';
 import hooks from './hooks.js';
 import { module, unnamedModule } from './module.js';
 import onUncaughtException from './on-uncaught-exception.js';
@@ -21,57 +21,155 @@ import version from './version.js';
 
 // Imports that help with init
 import { initBrowser } from './browser/browser-runner.js';
-import exportQUnit from './export.js';
 
+// Finalise internal state and exports before we export the API
 config.currentModule = unnamedModule;
 config._pq = new ProcessingQueue();
 
-const QUnit = {
+const assert = Assert.prototype;
+
+const isLocal = (window && window.location && window.location.protocol === 'file:');
+
+const begin = createRegisterCallbackFunction('begin');
+const done = createRegisterCallbackFunction('done');
+const log = createRegisterCallbackFunction('log');
+const moduleDone = createRegisterCallbackFunction('moduleDone');
+const moduleStart = createRegisterCallbackFunction('moduleStart');
+const testDone = createRegisterCallbackFunction('testDone');
+const testStart = createRegisterCallbackFunction('testStart');
 
-  // Figure out if we're running the tests from a server or not
-  isLocal: (window && window.location && window.location.protocol === 'file:'),
+const only = test.only;
+const skip = test.skip;
+const todo = test.todo;
 
-  // Expose the current QUnit version
-  version,
+// Export the API
+//
+// * ESM export
+//   - Node.js
+//   - browser
+//   - any other ESM-capable JS engine
+//
+// * globalThis
+//   - browser (globalThis === window)
+//   - Web Worker (globalThis === self)
+//   - Node.js
+//   - SpiderMonkey (mozjs)
+//   - Rhino 7.14+
+//   - any other embedded JS engine
+//
+// The following are handled by the separate export-commonjs.js file:
+//
+// * CommonJS module.exports (commonjs2)
+//   - Node.js
+//
+// * CommonJS exports (commonjs, https://wiki.commonjs.org/wiki/Modules):
+//   - Rhino
 
+export {
+  assert,
+  begin,
   config,
+  diff,
+  done,
+  dump,
+  equiv,
+  hooks,
+  is,
+  isLocal,
+  log,
+  module,
+  moduleDone,
+  moduleStart,
+  objectType,
+  on,
+  only,
+  onUncaughtException,
+  pushFailure,
+  reporters,
+  skip,
   stack,
+  start,
+  test,
+  testDone,
+  testStart,
+  todo,
   urlParams,
+  version
+};
 
+const QUnit = {
+  assert,
+  begin,
+  config,
   diff,
+  done,
   dump,
   equiv,
-  reporters,
   hooks,
   is,
-  on,
+  isLocal,
+  log,
+  module,
+  moduleDone,
+  moduleStart,
   objectType,
+  on,
+  only,
   onUncaughtException,
   pushFailure,
-
-  begin: createRegisterCallbackFunction('begin'),
-  done: createRegisterCallbackFunction('done'),
-  log: createRegisterCallbackFunction('log'),
-  moduleDone: createRegisterCallbackFunction('moduleDone'),
-  moduleStart: createRegisterCallbackFunction('moduleStart'),
-  testDone: createRegisterCallbackFunction('testDone'),
-  testStart: createRegisterCallbackFunction('testStart'),
-
-  assert: Assert.prototype,
-  module,
+  reporters,
+  skip,
+  stack,
   start,
   test,
-
-  // alias other test flavors for easy access
-  todo: test.todo,
-  skip: test.skip,
-  only: test.only
+  testDone,
+  testStart,
+  todo,
+  urlParams,
+  version
 };
 
 // Inject the exported QUnit API for use by reporters in start()
 config._QUnit = QUnit;
 
-exportQUnit(QUnit);
+// Support: require('qunit').QUnit
+//
+// For interop and consistency between Node.js `module.exports = QUnit`
+// and CommonJS environments `exports.QUnit = QUnit`, the below will
+// effectively assign `module.exports.QUnit = QUnit` as well.
+QUnit.QUnit = QUnit;
+
+// Support: named import
+//
+//   import { QUnit } from 'qunit'
+//
+export { QUnit };
+
+// Support: default import
+//
+//   import QUnit from 'qunit'
+//
+export default QUnit;
+
+if (window && document) {
+  // In browsers, throw if QUnit is loaded a second time.
+  // This must not throw if a global called "QUnit" exists for preconfigurion,
+  // in that case we simply upgrade/replace it with the proper export.
+  // Such preconfig global would only have QUnit.config set, not e.g. QUnit.version.
+  if (globalThis.QUnit && globalThis.QUnit.version) {
+    throw new Error('QUnit has already been defined.');
+  }
+}
+
+// Ensure the global is available in all environments.
+//
+// For backward compatibility, we only enforce load-once in browsers above.
+// In other environments QUnit is accessible via import/require() and may
+// load multiple times, including different versions from different sources.
+// Callers decide whether to make their secondary instance global or not.
+if (!globalThis.QUnit || !globalThis.QUnit.version) {
+  globalThis.QUnit = QUnit;
+}
 
 if (window && document) {
   initBrowser(QUnit, window, document);

src/core/version.js

@@ -1,2 +1,3 @@
+// Expose the current QUnit version
 // Replaced by /rollup.config.js using /build/dist-replace.js
 export default '@VERSION';