I am using Jest with TypeScript. Despite the fact that my code works and I can build my project, Visual Studio Code throws me that error for all Jest methods (describe()
, test()
...):
Cannot find name 'describe'. Do you need to install type definitions for a test runner? Try `npm i @types/jest` or `npm i @types/mocha`.ts(2582)
I have src
and tests
directories that are separated. I followed configurations found on the Internet but it doesn't change anything, what am I missing? The only way so far is to include my tests
folder in the include
setting in tsconfig
, which is bad because it's built in the dist
directory.
Dev dependencies installed: jest ts-jest @types/jest
tsconfig.json
{
"compilerOptions": {
"sourceMap": true,
"module": "commonjs",
"moduleResolution": "node",
"esModuleInterop": true,
"allowJs": true,
"jsx": "react",
"target": "es5",
"lib": ["dom", "dom.iterable", "esnext"],
"baseUrl": "./",
"paths": {
"*": ["src/*"]
},
"typeRoots": ["./node_modules/@types"],
"types": ["node", "jest"]
},
"strict": true,
"compileOnSave": false,
"include": ["src"]
}
jest.config.js
module.exports = {
roots: ['<rootDir>'],
preset: 'ts-jest',
testRegex: 'tests/src/.*\\.test.(js|jsx|ts|tsx)$',
transform: {
'^.+\\.tsx?$': 'ts-jest',
},
transformIgnorePatterns: [],
snapshotSerializers: ['enzyme-to-json/serializer'],
moduleDirectories: ['node_modules', 'src', 'tests'],
moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
moduleNameMapper: {
'\\.(css|scss|jpg|png|svg)$': 'mocks/empty.ts',
},
setupFilesAfterEnv: ['<rootDir>/tests/jest.setup.ts'],
collectCoverage: true,
collectCoverageFrom: ['src/**/*.{js{,x},ts{,x}}', '!src/index.tsx', '!src/custom.d.ts'],
}
Jest is an open-source testing framework built on JavaScript, designed majorly to work with React and React Native based web applications. Often, unit tests are not very useful when run on the frontend of any software. This is mostly because unit tests for the front-end require extensive, time-consuming configuration.
Who uses Jest? 894 companies reportedly use Jest in their tech stacks, including Airbnb, Facebook, and Instagram.
jest. It. only JavaScript and Node.
To create a test case in Jest we use the test() function. It takes a test name string and handler function as the first two arguments. The test() function can also be called under the alias - it() .
Just include jest
as typeAcquisition
in your tsconfig.json
like:
// tsconfig.json
{
"compilerOptions": { /* ... */ },
"typeAcquisition": { "include": ["jest"] },
// ... your other options go here
}
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