build: lint JavaScript and JSON from one eslint config

.github/linters/eslint.config.mjs

@@ -0,0 +1,5 @@
+// super-linter resolves JAVASCRIPT_ES_CONFIG_FILE under LINTER_RULES_PATH
+// (.github/linters), so this re-exports the repo's config. That keeps one
+// source of truth for `npm run lint` and for super-linter's JAVASCRIPT_ES,
+// JSON and JSONC linters, which all share this config.
+export { default } from '../../eslint.config.mjs'

.github/workflows/linter.yml

@@ -55,14 +55,6 @@ jobs:
           STRIP_DEFAULT_WORKSPACE_FOR_REGEX: true
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           VALIDATE_ALL_CODEBASE: true
-          # ci.yml already runs `npm run lint`, which is this repo's eslint and
-          # this repo's eslint.config.mjs. super-linter cannot be pointed at that
-          # config instead: JAVASCRIPT_ES_CONFIG_FILE is shared with the JSON,
-          # JSONC and VUE linters, and our config has no JSON language support,
-          # so reusing it would silently stop linting JSON. Rather than lint JS
-          # twice under two different rule sets, defer to ci.yml and let
-          # super-linter keep its own config for JSON/JSONC.
-          VALIDATE_JAVASCRIPT_ES: false
           VALIDATE_JSCPD: false
           VALIDATE_HTML: false
           # Biome is a competing formatter/linter: it wants semicolons and

eslint.config.mjs

@@ -1,18 +1,31 @@
 // See: https://eslint.org/docs/latest/use/configure/configuration-files
 
 import js from '@eslint/js'
+import json from '@eslint/json'
 import jest from 'eslint-plugin-jest'
 import prettierRecommended from 'eslint-plugin-prettier/recommended'
 import globals from 'globals'
 
+// super-linter lints JavaScript and JSON with a single eslint config, so this
+// file covers both. None of the shared JavaScript configs below declare `files`
+// of their own, which would apply their rules to the JSON files too, so they
+// are scoped explicitly.
+const jsFiles = ['**/*.js', '**/*.mjs', '**/*.cjs']
+
 export default [
   {
     ignores: ['**/coverage', '**/dist', '**/linter', '**/node_modules']
   },
-  js.configs.recommended,
-  jest.configs['flat/recommended'],
-  prettierRecommended,
+
+  ...[
+    js.configs.recommended,
+    jest.configs['flat/recommended'],
+    prettierRecommended
+  ].map((config) => ({ ...config, files: jsFiles })),
+
   {
+    files: jsFiles,
+
     languageOptions: {
       globals: {
         ...globals.node,
@@ -32,5 +45,30 @@ export default [
       'no-unused-vars': 'off',
       'prettier/prettier': 'error'
     }
+  },
+
+  {
+    ...json.configs.recommended,
+    files: ['**/*.json'],
+    language: 'json/json'
+  },
+
+  {
+    // super-linter routes .jsonc through this config too, so cover it here
+    // rather than leaving it silently unlinted if a file is ever added.
+    ...json.configs.recommended,
+    files: ['**/*.jsonc'],
+    language: 'json/jsonc'
+  },
+
+  {
+    // npm generates the lockfile, and its `packages` map uses "" as the key for
+    // the root project. Turn off just that rule rather than skipping the file,
+    // so the remaining JSON checks still apply.
+    files: ['package-lock.json'],
+    language: 'json/json',
+    rules: {
+      'json/no-empty-keys': 'off'
+    }
   }
 ]

package.json

@@ -46,6 +46,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^10.0.1",
+    "@eslint/json": "^2.1.0",
     "@jest/globals": "^30.4.1",
     "@rollup/plugin-commonjs": "^29.0.3",
     "@rollup/plugin-json": "^6.1.0",