I'm currently in the process of migrating my TypeScript project to a (pnpm) monorepo setup and encountering difficulties with running tests successfully. The issue seems to be related to jest, as I have a jest.config.js file that specifies a custom testEnvironment written in TypeScript. After moving the specific project into the packages directory for the monorepo restructuring, jest throws an Error and refuses to run any tests:
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for C:\workspaces\repos\the-monorepo\packages\testproject\source\testtools\jsdom-environment-global.spec.ts
I attempted to resolve the problem using @swc/jest and ts-jest, consulted resources like How to use TypeScript in a Custom Test Environment file in Jest? only to wonder why it worked previously. Despite clearing jest cache and reinstalling all node_modules, the issue persisted. Suggestions about adding
"type": "module"Below is a snippet of how the jest.config.js appears:
/** @type {import('@jest/types').Config.InitialOptions} */
const config = {
silent: true,
testEnvironment: "<rootDir>/source/testtools/jsdom-environment-global.spec.ts",
roots: [
"<rootDir>/source"
],
maxWorkers: "50%",
transform: {
"^.+\\.(t|j)s$": ["@swc/jest", {
sourceMaps: "inline",
module: {
strict: false,
strictMode: false
},
jsc: {
target: "es2021",
parser: {
syntax: "typescript",
dynamicImport: true
}
}
}]
},
transformIgnorePatterns: [
"node_modules"
],
testMatch: [
"**/*/*.spec.ts",
"**/*/*.test.ts",
"!**/playwright-tests/**",
"!**/playwright-tests-smoke/**"
],
moduleFileExtensions: ["ts", "js", "node", "json"],
reporters: [
"default"
],
globals: {
self: {},
navigator: {},
jasmine: {},
__UNIT__: true
},
coverageDirectory: "test-results",
collectCoverage: false,
collectCoverageFrom: [
"./source/**/*.ts"
],
coveragePathIgnorePatterns: [
"/\\.spec\\.ts$/i",
"/.*node_modules.*/",
"/.*testtools.*/"
],
coverageReporters: [
"lcov", "cobertura"
],
coverageProvider: "v8",
resetMocks: true,
restoreMocks: true,
resetModules: true,
setupFilesAfterEnv: [
"jest-extended/all",
"<rootDir>/source/testtools/setup.spec.ts"
],
testPathIgnorePatterns: [
"<rootDir>/source/testtools/",
"<rootDir>/source/smoke-tests/",
"<rootDir>/source/performance-tests/",
"<rooDir>/source/playwright-tests/",
"<rooDir>/source/playwright-tests-smoke/"
],
moduleNameMapper: {
"^@test-helpers": "<rootDir>/source/testtools/index.spec.ts",
"^@test-tools/(.*)": "<rootDir>/source/testtools/$1",
'^(\\.{1,2}/.*)\\.js$': '$1'
}
};
module.exports = config;
The main question is why jest is struggling to interpret the testEnvironment when it's a TypeScript file?