➕ add jest as a test runner

.eslintrc.cjs

@@ -6,4 +6,13 @@ module.exports = {
   extends: [
     '@quero/typescript',
   ],
+  overrides: [{
+    files: '**/*.test.*',
+    globals: {
+      test: 'readonly',
+      describe: 'readonly',
+      it: 'readonly',
+      expect: 'readonly',
+    },
+  }],
 };

babel.config.cjs

@@ -0,0 +1,6 @@
+module.exports = {
+  presets: [
+    ['@babel/preset-env', {targets: {node: 'current'}}],
+    '@babel/preset-typescript',
+  ],
+};

jest.config.ts

@@ -0,0 +1,195 @@
+/*
+ * For a detailed explanation regarding each configuration property and type check, visit:
+ * https://jestjs.io/docs/configuration
+ */
+
+export default {
+  // All imported modules in your tests should be mocked automatically
+  // automock: false,
+
+  // Stop running tests after `n` failures
+  // bail: 0,
+
+  // The directory where Jest should store its cached dependency information
+  // cacheDirectory: "/tmp/jest_rs",
+
+  // Automatically clear mock calls, instances, contexts and results before every test
+  // clearMocks: false,
+
+  // Indicates whether the coverage information should be collected while executing the test
+  collectCoverage: true,
+
+  // An array of glob patterns indicating a set of files for which coverage information should be collected
+  // collectCoverageFrom: undefined,
+
+  // The directory where Jest should output its coverage files
+  coverageDirectory: "coverage",
+
+  // An array of regexp pattern strings used to skip coverage collection
+  // coveragePathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // Indicates which provider should be used to instrument code for coverage
+  // coverageProvider: "babel",
+
+  // A list of reporter names that Jest uses when writing coverage reports
+  // coverageReporters: [
+  //   "json",
+  //   "text",
+  //   "lcov",
+  //   "clover"
+  // ],
+
+  // An object that configures minimum threshold enforcement for coverage results
+  // coverageThreshold: undefined,
+
+  // A path to a custom dependency extractor
+  // dependencyExtractor: undefined,
+
+  // Make calling deprecated APIs throw helpful error messages
+  // errorOnDeprecated: false,
+
+  // The default configuration for fake timers
+  // fakeTimers: {
+  //   "enableGlobally": false
+  // },
+
+  // Force coverage collection from ignored files using an array of glob patterns
+  // forceCoverageMatch: [],
+
+  // A path to a module which exports an async function that is triggered once before all test suites
+  // globalSetup: undefined,
+
+  // A path to a module which exports an async function that is triggered once after all test suites
+  // globalTeardown: undefined,
+
+  // A set of global variables that need to be available in all test environments
+  // globals: {},
+
+  // The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
+  // maxWorkers: "50%",
+
+  // An array of directory names to be searched recursively up from the requiring module's location
+  // moduleDirectories: [
+  //   "node_modules"
+  // ],
+
+  // An array of file extensions your modules use
+  // moduleFileExtensions: [
+  //   "js",
+  //   "mjs",
+  //   "cjs",
+  //   "jsx",
+  //   "ts",
+  //   "tsx",
+  //   "json",
+  //   "node"
+  // ],
+
+  // A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
+  // moduleNameMapper: {},
+
+  // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+  // modulePathIgnorePatterns: [],
+
+  // Activates notifications for test results
+  // notify: false,
+
+  // An enum that specifies notification mode. Requires { notify: true }
+  // notifyMode: "failure-change",
+
+  // A preset that is used as a base for Jest's configuration
+  // preset: undefined,
+
+  // Run tests from one or more projects
+  // projects: undefined,
+
+  // Use this configuration option to add custom reporters to Jest
+  // reporters: undefined,
+
+  // Automatically reset mock state before every test
+  // resetMocks: false,
+
+  // Reset the module registry before running each individual test
+  // resetModules: false,
+
+  // A path to a custom resolver
+  // resolver: undefined,
+
+  // Automatically restore mock state and implementation before every test
+  // restoreMocks: false,
+
+  // The root directory that Jest should scan for tests and modules within
+  // rootDir: undefined,
+
+  // A list of paths to directories that Jest should use to search for files in
+  // roots: [
+  //   "<rootDir>"
+  // ],
+
+  // Allows you to use a custom runner instead of Jest's default test runner
+  // runner: "jest-runner",
+
+  // The paths to modules that run some code to configure or set up the testing environment before each test
+  // setupFiles: [],
+
+  // A list of paths to modules that run some code to configure or set up the testing framework before each test
+  // setupFilesAfterEnv: [],
+
+  // The number of seconds after which a test is considered as slow and reported as such in the results.
+  // slowTestThreshold: 5,
+
+  // A list of paths to snapshot serializer modules Jest should use for snapshot testing
+  // snapshotSerializers: [],
+
+  // The test environment that will be used for testing
+  // testEnvironment: "jest-environment-node",
+
+  // Options that will be passed to the testEnvironment
+  // testEnvironmentOptions: {},
+
+  // Adds a location field to test results
+  // testLocationInResults: false,
+
+  // The glob patterns Jest uses to detect test files
+  // testMatch: [
+  //   "**/__tests__/**/*.[jt]s?(x)",
+  //   "**/?(*.)+(spec|test).[tj]s?(x)"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+  // testPathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // The regexp pattern or array of patterns that Jest uses to detect test files
+  // testRegex: [],
+
+  // This option allows the use of a custom results processor
+  // testResultsProcessor: undefined,
+
+  // This option allows use of a custom test runner
+  // testRunner: "jest-circus/runner",
+
+  // A map from regular expressions to paths to transformers
+  // transform: undefined,
+
+  // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+  // transformIgnorePatterns: [
+  //   "/node_modules/",
+  //   "\\.pnp\\.[^\\/]+$"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+  // unmockedModulePathPatterns: undefined,
+
+  // Indicates whether each individual test should be reported during the run
+  // verbose: undefined,
+
+  // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+  // watchPathIgnorePatterns: [],
+
+  // Whether to use watchman for file crawling
+  // watchman: true,
+};

package.json

@@ -2,14 +2,24 @@
   "name": "test-lazy-let",
   "module": "index.ts",
   "type": "module",
+  "scripts": {
+    "test": "jest"
+  },
   "devDependencies": {
+    "@babel/core": "^7.18.10",
+    "@babel/preset-env": "^7.18.10",
+    "@babel/preset-typescript": "^7.18.6",
     "@quero/eslint-config-base": "^2.1.0",
     "@quero/eslint-config-typescript": "^1.2.2",
+    "@types/jest": "^28.1.7",
     "@typescript-eslint/eslint-plugin": "^5.33.1",
     "@typescript-eslint/parser": "^5.33.1",
+    "babel-jest": "^28.1.3",
     "bun-types": "^0.1.0",
     "eslint": "^8.22.0",
     "eslint-plugin-jest": "^26.8.3",
+    "jest": "^28.1.3",
+    "ts-node": "^10.9.1",
     "typescript": "^4.7.4"
   }
 }

tsconfig.json

@@ -9,6 +9,6 @@
     "allowJs": true,
 
     // "bun-types" is the important part
-    "types": ["bun-types"]
+    "types": ["bun-types", "jest"]
   }
 }