useESM option

The useESM option allows ts-jest to transform codes to ESM syntax if possible.

The default value is false, ts-jest will transform codes to CommonJS syntax.

Examples

JavaScript

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

TypeScript

import type { JestConfigWithTsJest } from 'ts-jest'

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

export default jestConfig

JSON

{
  // [...]
  "jest": {
    "transform": {
      // '^.+\\.[tj]sx?$' to process js/ts with `ts-jest`
      // '^.+\\.m?[tj]sx?$' to process js/ts/mjs/mts with `ts-jest`
      "^.+\\.tsx?$": [
        "ts-jest",
        {
          "useESM": true
        }
      ]
    }
  }
}