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How to use validateExtensionsToTreatAsEsm method in Jest

Best JavaScript code snippet using jest

normalize.js

Source:normalize.js

...499        'Running all tests instead.'500    )501  );502};503function validateExtensionsToTreatAsEsm(extensionsToTreatAsEsm) {504  if (!extensionsToTreatAsEsm || extensionsToTreatAsEsm.length === 0) {505    return;506  }507  function printConfig(opts) {508    const string = opts.map(ext => `'${ext}'`).join(', ');509    return _chalk().default.bold(`extensionsToTreatAsEsm: [${string}]`);510  }511  const extensionWithoutDot = extensionsToTreatAsEsm.some(512    ext => !ext.startsWith('.')513  );514  if (extensionWithoutDot) {515    throw createConfigError(`  Option: ${printConfig(516      extensionsToTreatAsEsm517    )} includes a string that does not start with a period (${_chalk().default.bold(518      '.'519    )}).520  Please change your configuration to ${printConfig(521    extensionsToTreatAsEsm.map(ext => (ext.startsWith('.') ? ext : `.${ext}`))522  )}.`);523  }524  if (extensionsToTreatAsEsm.includes('.js')) {525    throw createConfigError(526      `  Option: ${printConfig(527        extensionsToTreatAsEsm528      )} includes ${_chalk().default.bold(529        "'.js'"530      )} which is always inferred based on ${_chalk().default.bold(531        'type'532      )} in its nearest ${_chalk().default.bold('package.json')}.`533    );534  }535  if (extensionsToTreatAsEsm.includes('.cjs')) {536    throw createConfigError(537      `  Option: ${printConfig(538        extensionsToTreatAsEsm539      )} includes ${_chalk().default.bold(540        "'.cjs'"541      )} which is always treated as CommonJS.`542    );543  }544  if (extensionsToTreatAsEsm.includes('.mjs')) {545    throw createConfigError(546      `  Option: ${printConfig(547        extensionsToTreatAsEsm548      )} includes ${_chalk().default.bold(549        "'.mjs'"550      )} which is always treated as an ECMAScript Module.`551    );552  }553}554async function normalize(555  initialOptions,556  argv,557  configPath,558  projectIndex = Infinity559) {560  var _options$haste, _argv$_;561  const {hasDeprecationWarnings} = (0, _jestValidate().validate)(562    initialOptions,563    {564      comment: _utils.DOCUMENTATION_NOTE,565      deprecatedConfig: _Deprecated.default,566      exampleConfig: _ValidConfig.default,567      recursiveDenylist: [568        'collectCoverageOnlyFrom', // 'coverageThreshold' allows to use 'global' and glob strings on the same569        // level, there's currently no way we can deal with such config570        'coverageThreshold',571        'globals',572        'moduleNameMapper',573        'testEnvironmentOptions',574        'transform'575      ]576    }577  );578  let options = normalizePreprocessor(579    normalizeReporters(580      normalizeMissingOptions(581        normalizeRootDir((0, _setFromArgv.default)(initialOptions, argv)),582        configPath,583        projectIndex584      )585    )586  );587  if (options.preset) {588    options = await setupPreset(options, options.preset);589  }590  if (!options.setupFilesAfterEnv) {591    options.setupFilesAfterEnv = [];592  }593  if (594    options.setupTestFrameworkScriptFile &&595    options.setupFilesAfterEnv.length > 0596  ) {597    throw createConfigError(`  Options: ${_chalk().default.bold(598      'setupTestFrameworkScriptFile'599    )} and ${_chalk().default.bold(600      'setupFilesAfterEnv'601    )} cannot be used together.602  Please change your configuration to only use ${_chalk().default.bold(603    'setupFilesAfterEnv'604  )}.`);605  }606  if (options.setupTestFrameworkScriptFile) {607    options.setupFilesAfterEnv.push(options.setupTestFrameworkScriptFile);608  }609  options.testEnvironment = (0, _jestResolve().resolveTestEnvironment)({610    requireResolveFunction: require.resolve,611    rootDir: options.rootDir,612    testEnvironment:613      options.testEnvironment ||614      require.resolve(_Defaults.default.testEnvironment)615  });616  if (!options.roots && options.testPathDirs) {617    options.roots = options.testPathDirs;618    delete options.testPathDirs;619  }620  if (!options.roots) {621    options.roots = [options.rootDir];622  }623  if (624    !options.testRunner ||625    options.testRunner === 'circus' ||626    options.testRunner === 'jest-circus'627  ) {628    options.testRunner = require.resolve('jest-circus/runner');629  } else if (options.testRunner === 'jasmine2') {630    options.testRunner = require.resolve('jest-jasmine2');631  }632  if (!options.coverageDirectory) {633    options.coverageDirectory = path().resolve(options.rootDir, 'coverage');634  }635  setupBabelJest(options); // TODO: Type this properly636  const newOptions = {..._Defaults.default};637  if (options.resolver) {638    newOptions.resolver = (0, _utils.resolve)(null, {639      filePath: options.resolver,640      key: 'resolver',641      rootDir: options.rootDir642    });643  }644  validateExtensionsToTreatAsEsm(options.extensionsToTreatAsEsm);645  if (options.watchman == null) {646    options.watchman = _Defaults.default.watchman;647  }648  const optionKeys = Object.keys(options);649  optionKeys.reduce((newOptions, key) => {650    // The resolver has been resolved separately; skip it651    if (key === 'resolver') {652      return newOptions;653    } // This is cheating, because it claims that all keys of InitialOptions are Required.654    // We only really know it's Required for oldOptions[key], not for oldOptions.someOtherKey,655    // so oldOptions[key] is the only way it should be used.656    const oldOptions = options;657    let value;658    switch (key) {...

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What is Jest Framework
Advantages of Jest - Jest has 3,898,000 GitHub repositories, as mentioned on its official website. Learn what makes Jest special and why Jest has gained popularity among the testing and developer community.
Jest Installation - All the prerequisites and set up steps needed to help you start Jest automation testing.
Using Jest with NodeJS Project - Learn how to leverage Jest framework to automate testing using a NodeJS Project.
Writing First Test for Jest Framework - Get started with code-based tutorial to help you write and execute your first Jest framework testing script.
Jest Vocabulary - Learn the industry renowned and official jargons of the Jest framework by digging deep into the Jest vocabulary.
Unit Testing with Jest - Step-by-step tutorial to help you execute unit testing with Jest framework.
Jest Basics - Learn about the most pivotal and basic features which makes Jest special.
Jest Parameterized Tests - Avoid code duplication and fasten automation testing with Jest using parameterized tests. Parameterization allows you to trigger the same test scenario over different test configurations by incorporating parameters.
Jest Matchers - Enforce assertions better with the help of matchers. Matchers help you compare the actual output with the expected one. Here is an example to see if the object is acquired from the correct class or not. -

|it('check_object_of_Car', () => { expect(newCar()).toBeInstanceOf(Car); });| | :- |

Jest Hooks: Setup and Teardown - Learn how to set up conditions which needs to be followed by the test execution and incorporate a tear down function to free resources after the execution is complete.
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HTML Report Generation - Learn how to create a comprehensive HTML report based on your Jest test execution.
Testing React app using Jest Framework - Learn how to test your react web-application with Jest framework in this detailed Jest tutorial.
Test using LambdaTest cloud Selenium Grid - Run your Jest testing script over LambdaTest cloud-based platform and leverage parallel testing to help trim down your test execution time.
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Bonus: Import ES modules with Jest - ES modules are also known as ECMAScript modules. Learn how to best use them by importing in your Jest testing scripts.
Jest vs Mocha vs Jasmine - Learn the key differences between the most popular JavaScript-based testing frameworks i.e. Jest, Mocha, and Jasmine.
Jest FAQs(Frequently Asked Questions) - Explore the most commonly asked questions around Jest framework, with their answers.