Here are some different ways on how to set up Jest to support ESM. This applies for Jest v25, Node v13, and Babel v7.
Note: This article was written with Node v14 in mind (2021), things may have changed since.
Node v14 and Jest v26 support ESM natively with the
--experimental-vm-modules flag. Install cross-env, then add
NODE_OPTIONS to the scripts.test in package.json 2. See tne Jest documentation for more info (jest.io).
babel-jest. Configure Babel. We’ll use env.test here so not to interfere with your build process.
jest-esm-transformer - this is a preset configuration of Babel to support ESM transpilation.
As of March 2020, using
esm is currently not possible. Follow these threads for details.
buble-jest. Buble is an alternative to Babel. Note that as of 2021, this package hasn’t been updated since 2018.