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.

Example ​

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.ts
import type { JestConfigWithTsJest } from 'ts-jest'

const jestConfig: JestConfigWithTsJest = {
  // [...]
  moduleNameMapper: {
    '^@App/(.*)$': '<rootDir>/src/$1',
    '^lib/(.*)$': '<rootDir>/common/$1',
  },
}

export default jestConfig

// package.json
{
  // [...]
  "jest": {
    "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>/' } */),
}

// jest.config.ts
import { pathsToModuleNameMapper } from '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):
import { compilerOptions } from './tsconfig'
import type { JestConfigWithTsJest } from 'ts-jest'

const jestConfig: JestConfigWithTsJest = {
  // [...]
  roots: ['<rootDir>'],
  modulePaths: [compilerOptions.baseUrl], // <-- This will be set to 'baseUrl' value
  moduleNameMapper: pathsToModuleNameMapper(compilerOptions.paths /*, { prefix: '<rootDir>/' } */),
}

export default jestConfig

With extra options as 2nd argument: