Typeerror: cannot read property 'testenvironmentoptions' of undefined

Having difficulties fixing an error message “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined”?

Worry no more, because this article is for you.

In this article, we will discuss the possible causes of “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined”, and provide solutions to resolve the error.

But first, let us know what this error means.

What is Typeerror: cannot read property ‘testenvironmentoptions’ of undefined?

The error message “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” means that your code is trying to access the property ‘testenvironmentoptions’ of an object that has not been properly initialized or defined.

This error message typically occurs in JavaScript, and it can be caused by a variety of issues.

But before we go into those let’s define first some key terms that were found in the error.

What is testenvironmentoptions?

‘testenvironmentoptions’ is likely a property or variable name used in a JavaScript program or script.

It is not a built-in keyword in the JavaScript language, but rather a custom name that was chosen by the programmer who wrote the code.

Now, let’s discuss how the “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” error occurs.

How does Typeerror: cannot read property ‘testenvironmentoptions’ of undefined occurs?

The “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” is an error message that can occur in the Jest testing framework for JavaScript.

There are several possible reasons why this error might occur, such as:

Outdated version of Jest.
A conflict with another package or configuration that is interfering with Jest.
Not having the jest-environment-jsdom package installed.

1. Outdated version of Jest:

The first reason why “cannot read property ‘testenvironmentoptions’ of undefined” error occurs is because of an outdated version of Jest.

This means that the Jest framework is not able to recognize or interpret this property and may throw an error when it encounters it.

If the version of Jest being used is not up-to-date, it may not support certain features or options that are required by the code being tested.

2. A conflict with another package or configuration that is interfering with Jest:

Another reason why the error message “cannot read property ‘testenvironmentoptions’ of undefined” may occur in Jest is due to a conflict with another package or configuration that is interfering with Jest.

This means that there may be a clash between the configuration or behavior of Jest and another package or tool that is being used in the same project.

3. Not having the jest-environment-jsdom package installed:

Another reason why the error message “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” may occur in Jest is due to not having the ‘jest-environment-jsdom’ package installed.

This package is a required dependency for using Jest with the JSDOM environment, which is a popular tool for simulating a browser environment in Node.js.

Here’s an example code that could trigger the “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” error:

// Jest configuration file (jest.config.js)

module.exports = {
  testEnvironmentOptions: {
    // options for the JSDOM environment
    // ...
  },
  // other Jest configuration options
  // ...
}

In this code, we are setting the ‘testEnvironmentOptions’ property in the Jest configuration file.

However, if Jest is not able to recognize or interpret this property, it may throw an error such as:

Typeerror: cannot read property 'testenvironmentoptions' of undefined

Now let’s fix this error.

Typeerror: cannot read property ‘testenvironmentoptions’ of undefined – Solutions

Here are some ways to fix the “cannot read property ‘testenvironmentoptions’ of undefined” error, along with examples of how to implement them:

Solution 1 : Install jest-environment-jsdom:

To install jest-environment-jsdom, Open your terminal or command and run the following code:

With NPM:

npm install jest-environment-jsdom --save-dev

With Yarn:

yarn add jest-environment-jsdom --dev

If the error message still persists after trying the previous solutions.

You can try to install Jest and make sure that the versions of Jest and ‘jest-environment-jsdom’ are compatible with each other.

Here are the commands to install Jest and ‘jest-environment-jsdom’:

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

Once they are installed, make sure that their versions are compatible with each other by checking their version numbers in your ‘package.json’ file or by running the following command:

npm ls jest jest-environment-jsdom

Here is an example of how to install version 29.3.1 of Jest and ‘jest-environment-jsdom’:

With NPM:

npm install [email protected] --save-dev
npm install [email protected] --save-dev

With Yarn:

yarn add [email protected] --dev
yarn add [email protected] --dev

Solution 2: Deleting and reinstalling the ‘node_modules’ and ‘package-lock.json’ files:

Here are the commands to delete ‘node_modules’ and ‘package-lock.json’ files, clean the npm cache, and then re-install the packages:

For Windows:

rd /s /q "node_modules"
del package-lock.json
npm cache clean --force
npm install

For macOS/Linux:

rm -rf node_modules
rm -f package-lock.json
npm cache clean --force
npm install

After deleting the files and re-installing the packages, make sure to restart your IDE and test server.

If you are using VSCode, it is recommended to reboot it as it can sometimes glitch and need a restart.

Solution 3: Set testEnvironment to jsdom:

To fix the “cannot read property ‘testenvironmentoptions’ of undefined” error, ensure that the testEnvironment property is set to jsdom in your package.json or jest.config.js file.

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

You can do this by adding the following code:

module.exports = {
  testEnvironment: 'jsdom'
};

You can also set the testEnvironment property in your package.json file:

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

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

It’s also possible to set the test environment on a per-file basis using a docstring at the top of the file:

/**
 * @jest-environment jsdom
 */

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

This will ensure that the specified environment is used for all tests in the file.

So those are the alternative solutions that you can use to solve the “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” error.

Hoping that one or more of them helps you troubleshoot and resolve the error.

Here are the other fixed Python errors that you can visit, you might encounter them in the future.

typeerror unsupported operand type s for str and int

Conclusion

In conclusion, The “Typeerror: cannot read property ‘testenvironmentoptions’ of undefined” is an error message that occurs in the Jest testing framework for JavaScript.

It means that you are trying to access the property ‘testenvironmentoptions’ of an object that has not been properly initialized or defined.

To solve this error you make sure that you have the jest-environment-jsdom package installed and
your versions of jest and jest-environment-jsdom are compatible.

By following the given solution, surely you can fix the error quickly and proceed to your coding project again.

I hope this article helps you to solve your problem regarding a Typeerror stating “cannot read property ‘testenvironmentoptions’ of undefined”.

We’re happy to help you.

Happy coding! Have a Good day and God bless.