babel-jest with ES6 modules

Question

I'm happily using node 8.6 with the experimental ES6 modules option (--experimental-modules) turned on. This allows me to perfectly write plain ES2015 code for node without the need of babel.

The problem is when I try to create some tests with jest, it fails complaining about a syntax error: "Unexpected token import".

The .babelrc configuration is the following:

{ "env": { "test": { "presets": [ ["env", { "targets": { "node": "8.6" } }] ] } } }

My jest.config.js is as follows:

module.exports = { testMatch: ['/tests/**/*.js', '**/?(*.)test.js'], }

The error thrown:

 /app/tests/integration/controller/data-provider/Credentials/CredentialsList.action.test.js:2 import { Credentials, AdWordsCredentials } from '../../../../../imports/models/data-provider/Credentials.mjs'; ^^^^^^ SyntaxError: Unexpected token import at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:305:17) at Generator.next (<anonymous>) at Promise (<anonymous>)

Relevant packages:

babel-core@^6.26.0
jest@^21.2.1
babel-jest@^21.2.0
babel-preset-env@^1.6.0

Any help will be appreciated. Thanks :)

UPDATE: I've tried calling jest without babel, with the following command, without any change: node --experimental-modules node_modules/.bin/jest

Any luck figuring this out? 2 years later I still have the same problem. — geoidesic
– geoidesic, Commented Nov 5, 2019 at 21:09

joshuanapoli · Accepted Answer · 2017-12-30 18:32:40Z

Jest has a custom implementation of require to help with mocking. Unfortunately, this makes jest incompatible with node --experimental-modules. Babel is probably the best way to use ES6 modules with jest. See https://github.com/facebook/jest/issues/4842

James Suárez · Accepted Answer · 2019-03-02 21:28:41Z

I was not used jest, and I am not sure if this will solve, but I hope this can help you.

Node still doesn't support all syntax. If you really are looking a faster way to start develop, using source code with all features of Ecmascript2017, you need a module like @kawix/core https://www.npmjs.com/package/@kawix/core

How the README.md says, allows you to use all features including "imports" and "async/await" and also supports typescript, and other good features all without a LOT OF DEPENDENCIES. You can use directly with cli:

> npm install -g @kawix/core > kwcore /path/to/fullsyntaxtsupport.js

Or if you want inclute programatically, create a file example main.js to import the fully syntax file

var kawix= require("@kawix/core") kawix.KModule.injectImport() kawix.KModule.import("/path/to/fullsyntaxtsupport.js").catch(function(e){ console.error("Some error: ",e) })

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