ESM: remove code for Node versions <10

.eslintrc.yml

@@ -35,7 +35,7 @@ overrides:
     env:
       browser: false
   - files:
-      - esm-utils.js
+      - lib/nodejs/esm-utils.js
       - rollup.config.js
       - rollup_no-ie11.config.js
       - scripts/pick-from-package-json.js

lib/cli/run-helpers.js

@@ -14,7 +14,7 @@ const {watchRun, watchParallelRun} = require('./watch-run');
 const collectFiles = require('./collect-files');
 const {format} = require('util');
 const {createInvalidLegacyPluginError} = require('../errors');
-const {requireOrImport} = require('../esm-utils');
+const {requireOrImport} = require('../nodejs/esm-utils');
 const PluginLoader = require('../plugin-loader');
 
 /**

lib/mocha.js

@@ -13,9 +13,7 @@ var growl = require('./nodejs/growl');
 var utils = require('./utils');
 var mocharc = require('./mocharc.json');
 var Suite = require('./suite');
-var esmUtils = utils.supportsEsModules(true)
-  ? require('./esm-utils')
-  : undefined;
+var esmUtils = require('./nodejs/esm-utils');
 var createStatsCollector = require('./stats-collector');
 const {
   warn,
@@ -460,12 +458,6 @@ Mocha.prototype.loadFilesAsync = function() {
   var suite = this.suite;
   this.lazyLoadFiles(true);
 
-  if (!esmUtils) {
-    return new Promise(function(resolve) {
-      self.loadFiles(resolve);
-    });
-  }
-
   return esmUtils.loadFilesAsync(
     this.files,
     function(file) {

lib/utils.js

@@ -565,32 +565,6 @@ exports.defineConstants = function(obj) {
   return Object.freeze(exports.createMap(obj));
 };
 
-/**
- * Whether current version of Node support ES modules
- *
- * @description
- * Versions prior to 10 did not support ES Modules, and version 10 has an old incompatible version of ESM.
- * This function returns whether Node.JS has ES Module supports that is compatible with Mocha's needs,
- * which is version >=12.11.
- *
- * @param {partialSupport} whether the full Node.js ESM support is available (>= 12) or just something that supports the runtime (>= 10)
- *
- * @returns {Boolean} whether the current version of Node.JS supports ES Modules in a way that is compatible with Mocha
- */
-exports.supportsEsModules = function(partialSupport) {
-  if (!exports.isBrowser() && process.versions && process.versions.node) {
-    var versionFields = process.versions.node.split('.');
-    var major = +versionFields[0];
-    var minor = +versionFields[1];
-
-    if (!partialSupport) {
-      return major >= 13 || (major === 12 && minor >= 11);
-    } else {
-      return major >= 10;
-    }
-  }
-};
-
 /**
  * Returns current working directory
  *

package.json

@@ -175,17 +175,17 @@
   ],
   "browser": {
     "./index.js": "./browser-entry.js",
-    "./lib/nodejs/growl.js": "./lib/browser/growl.js",
-    "./lib/esm-utils.js": false,
+    "./lib/nodejs/growl.js": "./lib/browser/growl.js",    
     "fs": false,
     "path": false,
     "supports-color": false,
-    "./lib/nodejs/serializer.js": false,
-    "./lib/nodejs/worker.js": false,
     "./lib/nodejs/buffered-worker-pool.js": false,
+    "./lib/nodejs/esm-utils.js": false,
+    "./lib/nodejs/file-unloader.js": false,
     "./lib/nodejs/parallel-buffered-runner.js": false,
+    "./lib/nodejs/serializer.js": false,
+    "./lib/nodejs/worker.js": false,
     "./lib/nodejs/reporters/parallel-buffered.js": false,
-    "./lib/nodejs/file-unloader.js": false,
     "./lib/cli/index.js": false
   },
   "prettier": {

test/integration/esm.spec.js

@@ -1,15 +1,9 @@
 'use strict';
 var path = require('path');
 const {runMochaJSON: run, runMochaAsync} = require('./helpers');
-var utils = require('../../lib/utils');
-var args =
-  +process.versions.node.split('.')[0] >= 13 ? [] : ['--experimental-modules'];
+var args = [];
 
 describe('esm', function() {
-  before(function() {
-    if (!utils.supportsEsModules(true)) this.skip();
-  });
-
   it('should pass a passing esm test that uses esm', function(done) {
     var fixture = 'esm/esm-success.fixture.mjs';
     run(fixture, args, function(err, result) {
@@ -51,8 +45,6 @@ describe('esm', function() {
   });
 
   it('should recognize esm files ending with .js due to package.json type flag', function(done) {
-    if (!utils.supportsEsModules(false)) return this.skip();
-
     var fixture = 'esm/js-folder/esm-in-js.fixture.js';
     run(fixture, args, function(err, result) {
       if (err) {
@@ -69,11 +61,7 @@ describe('esm', function() {
     var fixture = 'esm/test-that-uses-dir-cjs-require.fixture.js';
     const result = await runMochaAsync(
       fixture,
-      [
-        ...args,
-        '--require',
-        path.resolve(__dirname, './fixtures/esm/dir-cjs-require')
-      ],
+      ['--require', path.resolve(__dirname, './fixtures/esm/dir-cjs-require')],
       {stdio: 'pipe'}
     );
 

test/integration/options/parallel.spec.js

@@ -6,7 +6,6 @@ const {
   getSummary,
   resolveFixturePath
 } = require('../helpers');
-const utils = require('../../../lib/utils');
 const pidtree = require('pidtree');
 
 const REPORTER_FIXTURE_PATH = resolveFixturePath('options/parallel/test-a');
@@ -108,27 +107,16 @@ describe('--parallel', function() {
   });
 
   describe('when used with ESM tests', function() {
-    const esmArgs =
-      Number(process.versions.node.split('.')[0]) >= 13
-        ? []
-        : ['--experimental-modules'];
-
-    before(function() {
-      if (!utils.supportsEsModules()) this.skip();
-    });
-
     it('should have the same result as with --no-parallel', async function() {
       const expected = getSummary(
         await invokeMochaAsync([
-          ...esmArgs,
           '--no-parallel',
           resolveFixturePath('esm/*.fixture.mjs')
         ])[1]
       );
 
       const actual = getSummary(
         await invokeMochaAsync([
-          ...esmArgs,
           '--parallel',
           resolveFixturePath('esm/*.fixture.mjs')
         ])[1]

test/integration/plugins/root-hooks.spec.js

@@ -1,7 +1,6 @@
 'use strict';
 
 var invokeMochaAsync = require('../helpers').invokeMochaAsync;
-var utils = require('../../../lib/utils');
 
 /**
  * Extracts root hook log messages from run results
@@ -99,38 +98,28 @@ describe('root hooks', function() {
     });
 
     describe('support ESM when type=module or .mjs extension', function() {
-      before(function() {
-        if (!utils.supportsEsModules()) this.skip();
-      });
-
       it('should run root hooks when provided via mochaHooks', function() {
         return expect(
-          runMochaForHookOutput(
-            [
-              '--require=' +
-                require.resolve(
-                  // as object
-                  '../fixtures/plugins/root-hooks/root-hook-defs-esm.fixture.mjs'
-                ),
-              '--require=' +
-                require.resolve(
-                  // as function
-                  '../fixtures/plugins/root-hooks/esm/root-hook-defs-esm.fixture.js'
-                ),
-              '--require=' +
-                require.resolve(
-                  // mixed with commonjs
-                  '../fixtures/plugins/root-hooks/root-hook-defs-a.fixture.js'
-                ),
+          runMochaForHookOutput([
+            '--require=' +
+              require.resolve(
+                // as object
+                '../fixtures/plugins/root-hooks/root-hook-defs-esm.fixture.mjs'
+              ),
+            '--require=' +
               require.resolve(
-                '../fixtures/plugins/root-hooks/root-hook-test.fixture.js'
-              )
-            ].concat(
-              +process.versions.node.split('.')[0] >= 13
-                ? []
-                : '--experimental-modules'
+                // as function
+                '../fixtures/plugins/root-hooks/esm/root-hook-defs-esm.fixture.js'
+              ),
+            '--require=' +
+              require.resolve(
+                // mixed with commonjs
+                '../fixtures/plugins/root-hooks/root-hook-defs-a.fixture.js'
+              ),
+            require.resolve(
+              '../fixtures/plugins/root-hooks/root-hook-test.fixture.js'
             )
-          ),
+          ]),
           'to be fulfilled with',
           [
             'afterAll',
@@ -147,10 +136,6 @@ describe('root hooks', function() {
     });
 
     describe('support ESM via .js extension w/o type=module', function() {
-      before(function() {
-        if (!utils.supportsEsModules()) this.skip();
-      });
-
       it('should fail due to ambiguous file type', function() {
         return expect(
           invokeMochaAsync(
@@ -160,11 +145,7 @@ describe('root hooks', function() {
                   // as object
                   '../fixtures/plugins/root-hooks/root-hook-defs-esm-broken.fixture.js'
                 )
-            ].concat(
-              +process.versions.node.split('.')[0] >= 13
-                ? []
-                : '--experimental-modules'
-            ),
+            ],
             'pipe'
           )[1],
           'when fulfilled',

test/unit/mocha.spec.js

@@ -78,7 +78,6 @@ describe('Mocha', function() {
     Suite = sinon.stub(Mocha, 'Suite').returns(suite);
     Suite.constants = {};
 
-    sinon.stub(utils, 'supportsEsModules').returns(false);
     sinon.stub(errors, 'warn');
     sinon.stub(utils, 'isString');
     sinon.stub(utils, 'noop');