Run tests in a native Node.js ESM environment (#13966)

Author: nicolo-ribaudo

.eslintrc.cjs

@@ -4,10 +4,22 @@ const path = require("path");
 
 const cjsGlobals = ["__dirname", "__filename", "require", "module", "exports"];
 
+const testFiles = [
+  "packages/*/test/**/*.js",
+  "codemods/*/test/**/*.js",
+  "eslint/*/test/**/*.js",
+];
+const sourceFiles = exts => [
+  `packages/*/src/**/*.{${exts}}`,
+  `codemods/*/src/**/*.{${exts}}`,
+  `eslint/*/src/**/*.{${exts}}`,
+];
+
 module.exports = {
   root: true,
   plugins: [
     "import",
+    "node",
     "jest",
     "prettier",
     "@babel/development",
@@ -36,11 +48,7 @@ module.exports = {
       },
     },
     {
-      files: [
-        "packages/*/src/**/*.{js,ts,cjs}",
-        "codemods/*/src/**/*.{js,ts,cjs}",
-        "eslint/*/src/**/*.{js,ts,cjs}",
-      ],
+      files: sourceFiles("js,ts,cjs,mjs"),
       rules: {
         "@babel/development/no-undefined-identifier": "error",
         "@babel/development/no-deprecated-clone": "error",
@@ -51,9 +59,7 @@ module.exports = {
     },
     {
       files: [
-        "packages/*/test/**/*.js",
-        "codemods/*/test/**/*.js",
-        "eslint/*/test/**/*.js",
+        ...testFiles,
         "packages/babel-helper-transform-fixture-test-runner/src/helpers.{ts,js}",
         "test/**/*.js",
       ],
@@ -68,20 +74,21 @@ module.exports = {
         "jest/no-test-callback": "off",
         "jest/valid-describe": "off",
         "import/extensions": ["error", "always"],
+        "import/no-extraneous-dependencies": "off",
         "no-restricted-imports": ["error", { patterns: ["**/src/**"] }],
       },
     },
     {
-      files: [
-        "packages/*/src/**/*.{js,ts}",
-        "codemods/*/src/**/*.{js,ts}",
-        "eslint/*/src/**/*.{js,ts}",
-        "packages/*/test/**/*.js",
-        "codemods/*/test/**/*.js",
-        "eslint/*/test/**/*.js",
-        "packages/babel-helper-transform-fixture-test-runner/src/helpers.{ts,js}",
-        "test/**/*.js",
-      ],
+      files: testFiles,
+      rules: {
+        "node/no-unsupported-features": [
+          "error",
+          { version: "12.17.0", ignores: ["modules"] },
+        ],
+      },
+    },
+    {
+      files: [...sourceFiles("js,ts,mjs"), ...testFiles, "test/**/*.js"],
       excludedFiles: [
         // @babel/register is the require() hook, so it will always be CJS-based
         "packages/babel-register/**/*.{js,ts}",

.gitignore

@@ -52,7 +52,8 @@ package-lock.json
 /packages/babel-runtime-corejs3/core-js/**/*.js
 /packages/babel-runtime-corejs3/core-js-stable/**/*.js
 
-/packages/babel-register/test/.babel
+/packages/babel-register/test/.cache.babel
+/packages/babel-register/test/.index.babel
 /packages/babel-cli/test/tmp
 /packages/babel-node/test/tmp
 /packages/*/lib

codemods/babel-plugin-codemod-object-assign-to-object-spread/test/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

codemods/babel-plugin-codemod-optional-catch-binding/test/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-parser/test/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-plugin-development-internal/test/rules/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-plugin-development/test/rules/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-plugin/test/rules/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-tests/test/fixtures/package.json

@@ -0,0 +1 @@
+{ "type": "commonjs" }

eslint/babel-eslint-tests/test/helpers/verifyAndAssertMessages.js

@@ -31,7 +31,7 @@ export default function verifyAndAssertMessages(
           "../../../babel-eslint-shared-fixtures/config/babel.config.js",
         ),
       },
-      ...overrideConfig?.parserOptions,
+      ...(overrideConfig && overrideConfig.parserOptions),
     },
   });