Cannot resolve module on using jest

Cannot resolve module on using jest

If you are encountering the “Cannot resolve module” error when using Jest in your TypeScript project, don’t worry – you’re not alone. This error typically occurs when Jest is unable to find or resolve a module that you are trying to import. In this blog post, we will explore a couple of solutions to help you resolve this issue and get your tests running smoothly.

Solution 1: Configure Jest to resolve TypeScript modules

Jest needs to be configured to properly resolve TypeScript modules. To do this, you can add a jest.config.js file to the root of your project and include the following configuration:

// jest.config.js
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  moduleNameMapper: {
    '^@/(.*)$': '/src/$1',
  },
};

The preset: 'ts-jest' option tells Jest to use the ts-jest preset for TypeScript projects. The testEnvironment: 'node' option sets the test environment to Node.js. Finally, the moduleNameMapper option allows you to map module paths to specific directories.

With this configuration in place, Jest should be able to resolve your TypeScript modules correctly.

Solution 2: Install and configure ts-jest

If you haven’t already, you may need to install the ts-jest package and configure it to work with your TypeScript project. You can install it using npm:

npm install --save-dev ts-jest

Once installed, you can configure it by adding a jest.config.js file to the root of your project with the following content:

// jest.config.js
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
};

With this configuration, Jest will use ts-jest as the preset for TypeScript projects and set the test environment to Node.js.

Final Thoughts

The “Cannot resolve module” error when using Jest with TypeScript can be frustrating, but with the right configuration, you can overcome it. By either configuring Jest to resolve TypeScript modules or installing and configuring ts-jest, you should be able to resolve this issue and get back to running your tests without any problems.

Happy testing!