Breaking: Switch to ESM (fixes #35)

.editorconfig

@@ -0,0 +1,15 @@
+; EditorConfig file: https://EditorConfig.org
+; Install the "EditorConfig" plugin into your editor to use
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+
+[package.json]
+indent_size = 2

.eslintignore

@@ -4,5 +4,4 @@
 /coverage/
 /docs/
 /jsdoc/
-
-
+/dist/

.eslintrc.js → .eslintrc.cjs

@@ -27,9 +27,16 @@ module.exports = {
                 "no-restricted-syntax": ["error", {
                     selector: "CallExpression[callee.object.name='assert'][callee.property.name='doesNotThrow']",
                     message: "`assert.doesNotThrow()` should be replaced with a comment next to the code."
+                }],
+
+                // Overcome https://github.com/mysticatea/eslint-plugin-node/issues/250
+                "node/no-unsupported-features/es-syntax": ["error", {
+                    ignores: [
+                        "modules",
+                        "dynamicImport"
+                    ]
                 }]
             }
         }
-
     ]
 };

.github/workflows/ci.yml

@@ -11,7 +11,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: actions/setup-node@v1
+    - uses: actions/setup-node@v2
+      with:
+        node-version: '12.22.0'
     - name: Install Packages
       run: npm install
     - name: Lint Files
@@ -22,7 +24,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        node: [16.x, 15.x, 14.x, 13.x, 12.x, 10.x, "10.12.0"]
+        node: [16.x, 14.x, 12.x, "12.22.0"]
         include:
         - os: windows-latest
           node: "12.x"

lib/cascading-config-array-factory.js

@@ -17,19 +17,20 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
 
-const os = require("os");
-const path = require("path");
-const ConfigValidator = require("./shared/config-validator");
-const { emitDeprecationWarning } = require("./shared/deprecation-warnings");
-const { ConfigArrayFactory } = require("./config-array-factory");
-const { ConfigArray, ConfigDependency, IgnorePattern } = require("./config-array");
-const debug = require("debug")("eslintrc:cascading-config-array-factory");
+import os from "os";
+import path from "path";
+import ConfigValidator from "./shared/config-validator.js";
+import { emitDeprecationWarning } from "./shared/deprecation-warnings.js";
+import { ConfigArrayFactory } from "./config-array-factory.js";
+import { ConfigArray, ConfigDependency, IgnorePattern } from "./config-array/index.js";
+import debugOrig from "debug";
+
+const debug = debugOrig("eslintrc:cascading-config-array-factory");
 
 //------------------------------------------------------------------------------
 // Helpers
@@ -516,4 +517,4 @@ class CascadingConfigArrayFactory {
 // Public Interface
 //------------------------------------------------------------------------------
 
-module.exports = { CascadingConfigArrayFactory };
+export { CascadingConfigArrayFactory };

lib/config-array-factory.js

@@ -33,26 +33,30 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
 
-const fs = require("fs");
-const path = require("path");
-const importFresh = require("import-fresh");
-const stripComments = require("strip-json-comments");
-const ConfigValidator = require("./shared/config-validator");
-const naming = require("./shared/naming");
-const ModuleResolver = require("./shared/relative-module-resolver");
-const {
+import fs from "fs";
+import path from "path";
+import importFresh from "import-fresh";
+import stripComments from "strip-json-comments";
+import ConfigValidator from "./shared/config-validator.js";
+import * as naming from "./shared/naming.js";
+import * as ModuleResolver from "./shared/relative-module-resolver.js";
+import {
     ConfigArray,
     ConfigDependency,
     IgnorePattern,
     OverrideTester
-} = require("./config-array");
-const debug = require("debug")("eslintrc:config-array-factory");
+} from "./config-array/index.js";
+import debugOrig from "debug";
+
+import { createRequire } from "module";
+const require = createRequire(import.meta.url);
+
+const debug = debugOrig("eslintrc:config-array-factory");
 
 //------------------------------------------------------------------------------
 // Helpers
@@ -1096,4 +1100,4 @@ class ConfigArrayFactory {
     }
 }
 
-module.exports = { ConfigArrayFactory, createContext };
+export { ConfigArrayFactory, createContext };

lib/config-array/config-array.js

@@ -24,14 +24,13 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
 
-const { ExtractedConfig } = require("./extracted-config");
-const { IgnorePattern } = require("./ignore-pattern");
+import { ExtractedConfig } from "./extracted-config.js";
+import { IgnorePattern } from "./ignore-pattern.js";
 
 //------------------------------------------------------------------------------
 // Helpers
@@ -504,21 +503,21 @@ class ConfigArray extends Array {
     }
 }
 
-const exportObject = {
-    ConfigArray,
+/**
+ * Get the used extracted configs.
+ * CLIEngine will use this method to collect used deprecated rules.
+ * @param {ConfigArray} instance The config array object to get.
+ * @returns {ExtractedConfig[]} The used extracted configs.
+ * @private
+ */
+function getUsedExtractedConfigs(instance) {
+    const { cache } = internalSlotsMap.get(instance);
 
-    /**
-     * Get the used extracted configs.
-     * CLIEngine will use this method to collect used deprecated rules.
-     * @param {ConfigArray} instance The config array object to get.
-     * @returns {ExtractedConfig[]} The used extracted configs.
-     * @private
-     */
-    getUsedExtractedConfigs(instance) {
-        const { cache } = internalSlotsMap.get(instance);
+    return Array.from(cache.values());
+}
 
-        return Array.from(cache.values());
-    }
-};
 
-module.exports = exportObject;
+export {
+    ConfigArray,
+    getUsedExtractedConfigs
+};

lib/config-array/config-dependency.js

@@ -14,9 +14,8 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
-const util = require("util");
+import util from "util";
 
 /**
  * The class is to store parsers or plugins.
@@ -113,4 +112,4 @@ class ConfigDependency {
 /** @typedef {ConfigDependency<import("../../shared/types").Parser>} DependentParser */
 /** @typedef {ConfigDependency<import("../../shared/types").Plugin>} DependentPlugin */
 
-module.exports = { ConfigDependency };
+export { ConfigDependency };

lib/config-array/extracted-config.js

@@ -14,9 +14,8 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
-const { IgnorePattern } = require("./ignore-pattern");
+import { IgnorePattern } from "./ignore-pattern.js";
 
 // For VSCode intellisense
 /** @typedef {import("../../shared/types").ConfigData} ConfigData */
@@ -143,4 +142,4 @@ class ExtractedConfig {
     }
 }
 
-module.exports = { ExtractedConfig };
+export { ExtractedConfig };

lib/config-array/ignore-pattern.js

@@ -27,16 +27,17 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
 
-const assert = require("assert");
-const path = require("path");
-const ignore = require("ignore");
-const debug = require("debug")("eslintrc:ignore-pattern");
+import assert from "assert";
+import path from "path";
+import ignore from "ignore";
+import debugOrig from "debug";
+
+const debug = debugOrig("eslintrc:ignore-pattern");
 
 /** @typedef {ReturnType<import("ignore").default>} Ignore */
 
@@ -234,4 +235,4 @@ class IgnorePattern {
     }
 }
 
-module.exports = { IgnorePattern };
+export { IgnorePattern };

lib/config-array/index.js

@@ -2,15 +2,14 @@
  * @fileoverview `ConfigArray` class.
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
-const { ConfigArray, getUsedExtractedConfigs } = require("./config-array");
-const { ConfigDependency } = require("./config-dependency");
-const { ExtractedConfig } = require("./extracted-config");
-const { IgnorePattern } = require("./ignore-pattern");
-const { OverrideTester } = require("./override-tester");
+import { ConfigArray, getUsedExtractedConfigs } from "./config-array.js";
+import { ConfigDependency } from "./config-dependency.js";
+import { ExtractedConfig } from "./extracted-config.js";
+import { IgnorePattern } from "./ignore-pattern.js";
+import { OverrideTester } from "./override-tester.js";
 
-module.exports = {
+export {
     ConfigArray,
     ConfigDependency,
     ExtractedConfig,

lib/config-array/override-tester.js

@@ -16,12 +16,14 @@
  *
  * @author Toru Nagashima <https://github.com/mysticatea>
  */
-"use strict";
 
-const assert = require("assert");
-const path = require("path");
-const util = require("util");
-const { Minimatch } = require("minimatch");
+import assert from "assert";
+import path from "path";
+import util from "util";
+import minimatch from "minimatch";
+
+const { Minimatch } = minimatch;
+
 const minimatchOpts = { dot: true, matchBase: true };
 
 /**
@@ -220,4 +222,4 @@ class OverrideTester {
     }
 }
 
-module.exports = { OverrideTester };
+export { OverrideTester };

lib/flat-compat.js

@@ -3,16 +3,21 @@
  * @author Nicholas C. Zakas
  */
 
-"use strict";
-
 //-----------------------------------------------------------------------------
 // Requirements
 //-----------------------------------------------------------------------------
 
-const path = require("path");
-const environments = require("../conf/environments");
-const createDebug = require("debug");
-const { ConfigArrayFactory } = require("./config-array-factory");
+import path from "path";
+import { fileURLToPath } from "url";
+import { createRequire } from "module";
+
+import createDebug from "debug";
+import { ConfigArrayFactory } from "./config-array-factory.js";
+
+const dirname = path.dirname(fileURLToPath(import.meta.url));
+const require = createRequire(import.meta.url);
+
+const environments = require("../conf/environments.cjs");
 
 //-----------------------------------------------------------------------------
 // Helpers
@@ -223,8 +228,8 @@ class FlatCompat {
         this[cafactory] = new ConfigArrayFactory({
             cwd: baseDirectory,
             resolvePluginsRelativeTo,
-            eslintAllPath: path.resolve(__dirname, "../conf/eslint-all.js"),
-            eslintRecommendedPath: path.resolve(__dirname, "../conf/eslint-recommended.js")
+            eslintAllPath: path.resolve(dirname, "../conf/eslint-all.cjs"),
+            eslintRecommendedPath: path.resolve(dirname, "../conf/eslint-recommended.cjs")
         });
     }
 
@@ -305,4 +310,4 @@ class FlatCompat {
     }
 }
 
-exports.FlatCompat = FlatCompat;
+export { FlatCompat };