Add & configure ESlint; incl. plugins

Issue 2096

eslint.config.mjs

@@ -0,0 +1,57 @@
+/* global import */
+
+import globals from "globals";
+import pluginJs from "@eslint/js";
+import { FlatCompat } from "@eslint/eslintrc";
+import path from "path";
+import prettierConfig from "eslint-config-prettier";
+import requirejs from "eslint-plugin-requirejs";
+import { fileURLToPath } from "url";
+
+
+// This chunk needed to use older style shared eslint configs, e.g. airbnb-base
+// mimic CommonJS variables -- not needed if using CommonJS
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const compat = new FlatCompat({
+    baseDirectory: __dirname
+});
+
+export default [
+  // This object must contain no other properties than ignores in order for it
+  // to apply to all config objects in this array
+  { ignores: ["src/components/"] },
+  // Use the recommended config for JS files
+  pluginJs.configs.recommended,
+  // Use the popular airbnb-base config, but extend it with our own rules
+  ...compat.extends("airbnb-base"),
+  // Lint all the main MetacatUI files
+  {
+    name: "lint-views-models-and-collections",
+    files: ["src/**/*.js"],
+    plugins: {
+      requirejs
+    },
+    languageOptions: {
+      sourceType: "commonjs",
+      ecmaVersion: 2020,
+      globals: {
+        ...globals.browser,
+        ...globals.amd,
+        MetacatUI: "readonly",
+      }
+    },
+    // Use requirejs.configs.recommended.rules and some of our own rules
+    rules: {
+      ...requirejs.configs.recommended.rules,
+      "import/no-amd": "off", // We use AMD
+      "no-console": "off", // We allow console.log for now
+      "strict": ["error", "global"], // We use strict mode
+      "func-names": "off", // require and backbone need to use unnamed functions
+    }
+
+  },
+  // Allow the prettier plugin to override any conflicting rules
+  ...[].concat(prettierConfig),
+];