ts-jest

What is ts-jest?

ts-jest is an npm package that allows users to run tests written in TypeScript directly, without having to precompile them to JavaScript. It is a Jest transformer with source map support that lets you use Jest to test projects written in TypeScript.

What are ts-jest's main functionalities?

TypeScript testing

This feature allows you to write Jest tests in TypeScript. The code sample demonstrates a simple test for a sum function.

import sum from './sum';
test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

Source map support

Source map support for accurate stack traces in error messages, which is useful for debugging tests.

/* Source maps are automatically handled by ts-jest, so there's no specific code sample for this feature. It works under the hood to provide accurate stack traces in your tests. */

TypeScript configuration

Allows you to use your project's TypeScript configuration or specify a custom one for testing purposes.

/* ts-jest uses the tsconfig.json file in your project to understand how to compile your TypeScript code. You can also specify a different configuration file for ts-jest if needed. */

Coverage reports

Integrates with Jest's coverage reporting to include TypeScript files in coverage statistics.

/* To collect coverage, you can use Jest's built-in coverage collection feature with ts-jest. */
jest --coverage

Other packages similar to ts-jest

babel-jest

babel-jest is a Jest plugin that allows you to use Babel to transform your JavaScript code. It is similar to ts-jest but is focused on JavaScript with Babel transformations rather than TypeScript.

jest

Jest itself is a testing framework that can work with TypeScript when configured with the appropriate preprocessor (like ts-jest). It provides the overall testing framework that ts-jest plugs into.

mocha

Mocha is another testing framework that can be used with TypeScript when combined with a TypeScript compiler like ts-node. It is an alternative to Jest and thus to ts-jest, but it requires additional setup for working with TypeScript.

karma-typescript

karma-typescript is a Karma plugin that compiles and bundles TypeScript on the fly. It is similar to ts-jest in that it allows for testing TypeScript code, but it is designed to work within the Karma test runner ecosystem.

README

ts-jest

A Jest transformer with source map support that lets you use Jest to test projects written in TypeScript.

It supports all features of TypeScript including type-checking. Read more about Babel7 + preset-typescript vs TypeScript (and ts-jest).

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We are not doing semantic versioning and 23.10 is a re-write, run npm i -D ts-jest@"<23.10.0" to go back to the previous version

View the online documentation (usage & technical)

Ask for some help in the Jest Discord community or ts-jest GitHub Discussion

Before reporting any issues, be sure to check the troubleshooting page

We're looking for collaborators! Want to help improve ts-jest?

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Getting Started

These instructions will get you setup to use ts-jest in your project. For more detailed documentation, please check online documentation.

	using npm	using yarn
Prerequisites	npm i -D jest typescript	yarn add --dev jest typescript
Installing	npm i -D ts-jest @types/jest	yarn add --dev ts-jest @types/jest
Creating config	npx ts-jest config:init	yarn ts-jest config:init
Running tests	npm test or npx jest	yarn test or yarn jest

Built With

• TypeScript - JavaScript that scales
• Jest - Delightful JavaScript Testing
• ts-jest - Jest transformer for TypeScript (yes, ts-jest uses itself for its tests)

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

Versioning

We DO NOT use SemVer for versioning. Though you can think about SemVer when reading our version, except our major number follows the one of Jest. For the versions available, see the tags on this repository.

Authors/maintainers

• Kulshekhar Kabra - kulshekhar
• Gustav Wengel - GeeWee
• Ahn - ahnpnl
• Huafu Gandon - huafu

See also the list of contributors who participated in this project.

Supporters

• JetBrains has been kind enough to support ts-jest with an open source license.

License

This project is licensed under the MIT License - see the LICENSE.md file for details