TypeScript Config option

The tsconfig option allows you to define which tsconfig JSON file to use. An inline compiler options object can also be specified instead of a file path.

By default ts-jest will try to find a tsconfig.json in your project. If it cannot find one, it will use the default TypeScript compiler options; except, ES2015 is used as target instead of ES5.

If you need to use defaults and force ts-jest to use the defaults even if there is a tsconfig.json in your project, you can set this option to false.

Examples

Path to a tsconfig file

The path should be relative to the current working directory where you start Jest from. You can also use <rootDir> in the path to start from the project root dir.

JavaScript

// jest.config.js
/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        tsconfig: 'tsconfig.test.json',
      },
    ],
  },
}

TypeScript

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

const jestConfig: JestConfigWithTsJest = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        tsconfig: 'tsconfig.test.json',
      },
    ],
  },
}

export default jestConfig

JSON

// package.json
{
  // [...]
  "jest": {
    "transform": {
      // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
      // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
      "^.+\\.tsx?$": [
        "ts-jest",
        {
          "tsconfig": "tsconfig.test.json"
        }
      ]
    }
  }
}

Inline compiler options

Refer to the TypeScript compiler options for reference. It's basically the same object you'd put in your tsconfig.json's compilerOptions.

JavaScript

// jest.config.js
/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        tsconfig: {
          importHelpers: true,
        },
      },
    ],
  },
}

TypeScript

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

const jestConfig: JestConfigWithTsJest = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        tsconfig: {
          importHelpers: true,
        },
      },
    ],
  },
}

export default jestConfig

JSON

// package.json
{
  // [...]
  "jest": {
    "transform": {
      // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
      // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
      "^.+\\.tsx?$": [
        "ts-jest",
        {
          "tsconfig": {
            "importHelpers": true
          }
        }
      ]
    }
  }
}

Disable auto-lookup

By default ts-jest will try to find a tsconfig.json in your project. But you may not want to use it at all and keep TypeScript default options. You can achieve this by setting tsconfig to false.

JavaScript

// jest.config.js
/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        tsconfig: false,
      },
    ],
  },
}

TypeScript

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

const jestConfig: JestConfigWithTsJest = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        tsconfig: false,
      },
    ],
  },
}

export default jestConfig

JSON

// package.json
{
  // [...]
  "jest": {
    "transform": {
      // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
      // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
      "^.+\\.tsx?$": [
        "ts-jest",
        {
          "tsconfig": {
            "tsconfig": false
          }
        }
      ]
    }
  }
}