chore: update ESLint and Jest configuration

Author: jrobinsonc

eslint.config.js

@@ -1,15 +1,15 @@
 import globals from 'globals';
 import eslint from '@eslint/js';
 import tseslint from 'typescript-eslint';
-import eslintConfigPrettier from 'eslint-config-prettier';
+import eslintPluginPrettierRecommended from 'eslint-plugin-prettier/recommended';
 import eslintPluginUnicorn from 'eslint-plugin-unicorn';
 
 export default tseslint.config(
   eslint.configs.recommended,
   tseslint.configs.strictTypeChecked,
   tseslint.configs.stylisticTypeChecked,
   eslintPluginUnicorn.configs['flat/recommended'],
-  eslintConfigPrettier,
+  eslintPluginPrettierRecommended,
   {
     languageOptions: {
       globals: globals.node,
@@ -19,8 +19,100 @@ export default tseslint.config(
       },
     },
   },
+  {
+    files: ['src/**/*.ts', 'tests/**/*.ts'],
+    rules: {
+      'no-console': 'warn',
+      'no-debugger': 'warn',
+      'no-empty-pattern': 'warn',
+      'no-empty': 'warn',
+      'no-param-reassign': 'warn',
+      'no-unreachable': 'warn',
+      'no-var': 'warn',
+      'no-warning-comments': 'warn',
+      'prefer-const': 'warn',
+      eqeqeq: 'warn',
+
+      'prettier/prettier': 'warn',
+
+      'unicorn/prevent-abbreviations': 'off',
+      'unicorn/prefer-optional-catch-binding': 'warn',
+      'unicorn/no-empty-file': 'warn',
+      'unicorn/prefer-set-has': 'warn',
+      /**
+       * There are situations where you might prefer to use `null` because
+       * `undefined` doesn't fit. For example, when merging one object into another
+       * with lodash's merge function, it completely ignores properties with
+       * `undefined` values and you may want to keep those properties.
+       */
+      'unicorn/no-null': 'off',
+
+      '@typescript-eslint/no-magic-numbers': 'warn',
+      '@typescript-eslint/no-unused-vars': 'warn',
+      '@typescript-eslint/no-unsafe-assignment': 'warn',
+      '@typescript-eslint/no-floating-promises': ['warn', { ignoreIIFE: true }],
+      '@typescript-eslint/no-empty-function': 'warn',
+      '@typescript-eslint/explicit-function-return-type': [
+        'warn',
+        {
+          allowExpressions: false,
+          allowTypedFunctionExpressions: true,
+          allowHigherOrderFunctions: false,
+          allowDirectConstAssertionInArrowFunctions: true,
+          allowConciseArrowFunctionExpressionsStartingWithVoid: false,
+          allowFunctionsWithoutTypeParameters: false,
+          allowedNames: [],
+          allowIIFEs: false,
+        },
+      ],
+      '@typescript-eslint/explicit-module-boundary-types': 'warn',
+      '@typescript-eslint/typedef': [
+        'warn',
+        {
+          arrayDestructuring: true,
+          objectDestructuring: true,
+          arrowParameter: true,
+          memberVariableDeclaration: true,
+          parameter: true,
+          propertyDeclaration: true,
+          variableDeclaration: true,
+          variableDeclarationIgnoreFunction: true,
+        },
+      ],
+      '@typescript-eslint/strict-boolean-expressions': 'warn',
+      '@typescript-eslint/no-unsafe-call': 'warn',
+      '@typescript-eslint/no-unsafe-member-access': 'warn',
+      '@typescript-eslint/no-for-in-array': 'warn',
+      '@typescript-eslint/consistent-type-exports': 'warn',
+      '@typescript-eslint/consistent-type-imports': 'warn',
+      '@typescript-eslint/no-shadow': 'warn',
+      '@typescript-eslint/require-await': 'warn',
+      '@typescript-eslint/no-explicit-any': 'warn',
+      '@typescript-eslint/no-unsafe-return': 'warn',
+      /**
+       * It's better to explicitly define the type. The implementation may change in the future,
+       * and you can forget to add the type if it's not there. Also, you may need to create a variable
+       * that could have several types and in this case it's better to explicitly define what are those types.
+       */
+      '@typescript-eslint/no-inferrable-types': 'off',
+      // /**
+      //  * The nullish coalescing operator only coalesces when the checked value is null or
+      //  * undefined, but what if you want to coalesce on any falsy value like an empty string?
+      //  * In that case you would need "||". This requires {"strictNullChecks": true}
+      //  */
+      // '@typescript-eslint/prefer-nullish-coalescing': 'off',
+    },
+  },
   {
     files: ['**/*.js'],
+    // TS rules are applied by default so we have to disable the
+    // type-checking rules for JS files.
     extends: [tseslint.configs.disableTypeChecked],
   },
+  // {
+  //   files: ['tests/**/*.ts'],
+  //   env: {
+  //     jest: true,
+  //   },
+  // },
 );

jest.config.js

@@ -10,4 +10,5 @@ export default {
   transform: {
     '^.+.ts$': ['ts-jest', {}],
   },
+  clearMocks: true,
 };

package.json

@@ -13,8 +13,8 @@
   },
   "scripts": {
     "check-types": "yarn tsc --noEmit --pretty",
-    "lint": "eslint ./src",
-    "lint:fix": "eslint ./src --fix",
+    "lint": "eslint '{src,tests}/**/*.ts'",
+    "lint:fix": "eslint '{src,tests}/**/*.ts' --fix",
     "dev": "tsx watch src/server.ts",
     "test": "jest",
     "test:watch": "jest --watch",
@@ -34,16 +34,14 @@
     "@types/node": "^22.10.10",
     "eslint": "^9.18.0",
     "eslint-config-prettier": "^10.0.1",
+    "eslint-plugin-prettier": "^5.2.3",
     "eslint-plugin-unicorn": "^56.0.1",
     "globals": "^15.14.0",
     "jest": "^29.7.0",
-    "prettier": "^3.4.2",
+    "prettier": "3.4.2",
     "ts-jest": "^29.2.5",
     "tsx": "^4.19.2",
     "typescript": "^5.7.3",
     "typescript-eslint": "^8.21.0"
-  },
-  "engines": {
-    "node": ">=22"
   }
 }