Add & configure ESlint; incl. plugins

Issue 2096

Author: robyngit

eslint.config.mjs

@@ -0,0 +1,114 @@
+import { FlatCompat } from "@eslint/eslintrc";
+import pluginJs from "@eslint/js";
+import path from "path";
+import { fileURLToPath } from "url";
+import globals from "globals";
+import prettierConfig from "eslint-config-prettier";
+import requirejs from "eslint-plugin-requirejs";
+import jsdoc from "eslint-plugin-jsdoc";
+
+// For compatibility with configs that don't use the new eslint flat config format:
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+// ---------------------------------------------------------------------
+// ESLINT RECOMMENDED:
+// Use the recommended config for JS files by eslint
+const eslintRecommendedConfig = pluginJs.configs.recommended;
+const eslintRulesOverrides = {
+  // Allow underscored names to explicitly indicate an argument is not used
+  "no-unused-vars": ["error", { argsIgnorePattern: "^_" }],
+};
+
+// ---------------------------------------------------------------------
+// AIRBNB JAVASCRIPT STYLE GUIDE:
+// Use the Airbnb style guide, excluding react- and node- specific rules & the
+// rule that disallows "use strict"
+const airbnbConfigs = [
+  ...compat.extends("eslint-config-airbnb-base/rules/best-practices"),
+  ...compat.extends("eslint-config-airbnb-base/rules/errors"),
+  ...compat.extends("eslint-config-airbnb-base/rules/style"),
+  ...compat.extends("eslint-config-airbnb-base/rules/variables"),
+  ...compat.extends("eslint-config-airbnb-base/rules/es6"),
+  ...compat.extends("eslint-config-airbnb-base/rules/imports"),
+];
+const airbnbRulesOverrides = {
+  // We are using the AMD/RequireJS module pattern
+  "import/no-amd": "off",
+  "import/no-commonjs": "off",
+};
+
+// ---------------------------------------------------------------------
+// JSDOCS:
+// Ensure JSDoc comments are used, and check validity
+const jsdocConfig = jsdoc.configs["flat/recommended"];
+const jsdocsRulesOverrides = {
+  // Non-standard JSDoc tags we use to generate documentation.
+  "jsdoc/check-tag-names": [
+    "error",
+    { definedTags: ["classcategory", "screenshot"] },
+  ],
+  // Avoiding this error would mean importing modules we don't use
+  "jsdoc/no-undefined-types": "off",
+};
+
+// ---------------------------------------------------------------------
+// REQUIREJS
+// Use all rules from the recommended config for RequireJS
+const requirejsConfig = {
+  name: "requirejs",
+  plugins: {
+    requirejs,
+  },
+  rules: {
+    ...requirejs.configs.recommended.rules,
+  },
+};
+
+// ---------------------------------------------------------------------
+// METACATUI OVERRIDES
+const metacatuiConfig = {
+  files: ["src/**/*.js"],
+  languageOptions: {
+    sourceType: "commonjs",
+    ecmaVersion: 2020,
+    globals: {
+      ...globals.browser,
+      ...globals.amd,
+      MetacatUI: "readonly",
+      google: "readonly",
+    },
+  },
+  // Override rules that are not compatible with MetacatUI
+  rules: {
+    ...eslintRulesOverrides,
+    ...airbnbRulesOverrides,
+    ...jsdocsRulesOverrides,
+  },
+};
+
+// Ignores must be a separate object to be treated as global
+const ignoreList = {
+  ignores: [
+    "src/components/",
+    "docs/",
+    "test/",
+    "node_modules/",
+    ".github",
+    "server.js",
+    "eslint.config.mjs",
+  ],
+};
+
+export default [
+  ignoreList,
+  eslintRecommendedConfig,
+  ...airbnbConfigs,
+  jsdocConfig,
+  requirejsConfig,
+  metacatuiConfig,
+  prettierConfig, // prettier must be the last config in the array
+];