Jest: Cannot read properties of undefined (reading 'testEnvironmentOptions')

# Jest: Cannot read properties of undefined (reading 'testEnvironmentOptions')

The Jest "TypeError: Cannot read properties of undefined (reading 'testEnvironmentOptions')" occurs for 2 main reasons:

1. Having incompatible versions of jest and jest-environment-jsdom installed.
2. Not having the jest-environment-jsdom package installed.

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TypeError: Cannot read properties of undefined (reading 'testEnvironmentOptions')
  at new JSDOMEnvironment (node_modules/jest-environment-jsdom/build/index.js:72:28)
  at async TestScheduler.scheduleTests (node_modules/@jest/core/build/TestScheduler.js:333:13)
TypeError: Cannot read properties of undefined (reading 'html')

# Install jest-environment-jsdom

Open your terminal in your project's root directory and run the following command to install jest-environment-jsdom.

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# 👇️ with NPM
npm install jest-environment-jsdom --save-dev

# 👇️ with YARN
yarn add jest-environment-jsdom --dev

If the error persists, install jest and make sure that your jest and jest-environment-jsdom versions match.

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# 👇️ with NPM
npm install jest --save-dev
npm install jest-environment-jsdom --save-dev

# 👇️ with YARN
yarn add jest --dev
yarn add jest-environment-jsdom --dev

You can check your versions of jest and jest-environment-jsdom in the devDependencies section of your package.json file.

Here is an example of installing version 29.3.1 of jest and jest-environment-jsdom.

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# 👇️ with NPM
npm install jest@29.3.1 --save-dev
npm install jest-environment-jsdom@29.3.1 --save-dev

# 👇️ with YARN
yarn add jest@29.3.1 --dev
yarn add jest-environment-jsdom@29.3.1 --dev

# Delete your node_modules and reinstall your dependencies

If the error is not resolved, try to delete your node_modules and package-lock.json (not package.json) files, re-run npm install and restart your test server.

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# 👇️ Windows - delete node_modules and package-lock.json
rd /s /q "node_modules"
del package-lock.json

# 👇️ macOS/Linux - delete node_modules and package-lock.json
rm -rf node_modules
rm -f package-lock.json

# 👇️ clean npm cache
npm cache clean --force

# 👇️ install packages
npm install

Make sure to restart your IDE and test server if the error persists. VSCode often glitches and needs a reboot.

# Set testEnvironment to jsdom in jest.config.js

If the error persists, make sure that the testEnvironment property is set to jsdom in your package.json or jest.config.js or jest.config.ts file.

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"jest": {
    "testEnvironment": "jsdom"
}

And do the same if you use a jest.config.js file.

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module.exports = {
    "testEnvironment": "jsdom"
}

Setting the testEnvironment property to jsdom allows us to test in the browser. Note that jsdom is the default testEnvironment in recent versions of jest.

If you are building a node service, set the testEnvironment property to node.

You can also set the test environment on a per-file basis with a docstring.

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/**
 * @jest-environment jsdom
 */

test('use jsdom in this test file', () => {
  const element = document.createElement('div');
  expect(element).not.toBeNull();
});

The documentation string at the top of the file makes it so the specified environment will be used for all tests in the file.

# Conclusion

To solve the Jest "TypeError: Cannot read properties of undefined (reading 'testEnvironmentOptions')", make sure:

1. You have the jest-environment-jsdom package installed.
2. Your versions of jest and jest-environment-jsdom are compatible.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Received: serializes to the same string Jest error [Solved]
• Consider using the "jsdom" test environment error [Solved]
• How to clear or disable the Cache in Jest [4 Ways]
• Testing exceptions in Jest (Sync and Async code)
• Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called
• Jest: Exceeded timeout of 5000 ms for a test. Add a timeout value to this test
• Check multiple arguments on multiple calls for Jest mocks
• How to reset Mock functions and Spies in Jest
• Jest: Your test suite is leaking memory. Please ensure all references are cleaned