ECMAScript Modules

With the warnings out of the way, this is how you activate ESM support in your tests.

1. Execute node with --experimental-vm-modules, e.g. node --experimental-vm-modules node_modules/jest/bin/jest.js or etc..

   On Windows, you can use cross-env to be able to set environment variables.

   If you use Yarn, you can use yarn node --experimental-vm-modules $(yarn bin jest). This command will also work if you use .

2. If you want to treat other file extensions (such as .jsx or .ts) as ESM, please use the extensionsToTreatAsEsm option.

Most of the differences are explained in Node’s documentation, but in addition to the things mentioned there, Jest injects a special variable into all executed files - the . To access this object in ESM, you need to import it from the @jest/globals module. To access this object in ESM, you need to import it from the @jest/globals module or use .

Please note that we currently don’t support jest.mock in a clean way in ESM, but that is something we intend to add proper support for in the future. Follow this issue for updates. Follow for updates.