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Version: 29.2

Paths mapping

If you use "baseUrl" and "paths" options in your tsconfig file, you should make sure the "moduleNameMapper" option in your Jest config is setup accordingly.

ts-jest provides a helper to transform the mapping from tsconfig to Jest config format, but it needs the .js version of the config file.


TypeScript config

With the below config in your tsconfig:

// tsconfig.json
"compilerOptions": {
"baseUrl": ".",
"paths": {
"@App/*": ["src/*"],
"lib/*": ["common/*"]

Jest config (without helper)

// jest.config.js
/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
// [...]
moduleNameMapper: {
'^@App/(.*)$': '<rootDir>/src/$1',
'^lib/(.*)$': '<rootDir>/common/$1',

Jest config (with helper)

// jest.config.js
const { pathsToModuleNameMapper } = require('ts-jest')
// In the following statement, replace `./tsconfig` with the path to your `tsconfig` file
// which contains the path mapping (ie the `compilerOptions.paths` option):
const { compilerOptions } = require('./tsconfig')

/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
// [...]
roots: ['<rootDir>'],
modulePaths: [compilerOptions.baseUrl], // <-- This will be set to 'baseUrl' value
moduleNameMapper: pathsToModuleNameMapper(compilerOptions.paths /*, { prefix: '<rootDir>/' } */),

With extra options as 2nd argument:

  • prefix: append prefix to each of mapped config in the result
  • useESM: when using type: module in package.json, TypeScript enforces users to have explicit js extension when importing a ts file. This option is to help pathsToModuleNameMapper to create a config to suit with this scenario.