Add linting

ESLint

.github/workflows/tests.yml

@@ -23,5 +23,8 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      - name: Lint code (ESLint)
+        run: npm run lint
+
       - name: Test code (Jest)
         run: npm run test

__tests__/getplayer.test.js

@@ -1,4 +1,4 @@
-import { describe, expect, test } from '@jest/globals';
+import { describe, expect } from '@jest/globals';
 import supertest from 'supertest';
 import { app, server } from '../src/app.ts';
 

eslint.config.js

@@ -0,0 +1,27 @@
+import globals from "globals";
+import pluginJs from "@eslint/js";
+import tseslint from "typescript-eslint";
+import pluginJest from "eslint-plugin-jest";
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+  {files: ["**/*.{js,mjs,cjs,ts}"]},
+  {languageOptions: { globals: globals.browser }},
+  {
+    // update this to match your test files
+    files: ['**/*.spec.js', '**/*.test.js'],
+    plugins: { jest: pluginJest },
+    languageOptions: {
+      globals: pluginJest.environments.globals.globals,
+    },
+    rules: {
+      'jest/no-disabled-tests': 'warn',
+      'jest/no-focused-tests': 'error',
+      'jest/no-identical-title': 'error',
+      'jest/prefer-to-have-length': 'warn',
+      'jest/valid-expect': 'error',
+    },
+  },
+  pluginJs.configs.recommended,
+  ...tseslint.configs.recommended,
+];