ts-jest
Advanced tools
Package description
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.
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 --coveragebabel-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 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 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 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
Note: This is currently just a hack and most likely not suitable for all setups.
This repo uses code from the source-map-support package to show errors with mapped locations.
To use this in its current form, clone this repo anywhere on your disk. Run npm install in it.
Create a symlink in the node_modules directory of your project to this directory:
ln -s path-to-typescript-jest
such that you effectively have a node_modules/typescript-jest directory.
Modify your project's package.json so that the jest section looks something like:
{
"jest": {
"scriptPreprocessor": "<rootDir>/node_modules/typescript-jest/preprocessor.js",
"testFileExtensions": [
"ts",
"tsx",
"js"
],
"moduleFileExtensions": [
"ts",
"tsx",
"js"
],
"unmockedModulePathPatterns": [
"<rootDir>/node_modules/react/",
"<rootDir>/node_modules/react-dom/",
"<rootDir>/node_modules/react-addons-test-utils/",
"<rootDir>/node_modules/typescript-jest/"
],
"globals": {
"__TS_CONFIG__": {
"module": "commonjs",
"jsx": "react"
}
}
}
}
This should allow you to write Jest tests in Typescript and be able to locate errors without any additional gymnastics.
If you have any suggestions/pull requests to turn this into a useful package, just open an issue and I'll be happy to work with you to improve this.
git clone https://github.com/kulshekhar/typescript-jest
cd typescript-jest
npm install
./test-init.sh
npm test
It is assumed that typescript and jest-cli are globally installed. If not, please do so:
npm i -g typescript jest-cli
FAQs
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The npm package ts-jest receives a total of 9,398,321 weekly downloads. As such, ts-jest popularity was classified as popular.
We found that ts-jest demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 3 open source maintainers collaborating on the project.
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