Does Jest support ES6 import/export?

Question

If I use import/export from ES6 then all my Jest tests fail with error:

Unexpected reserved word

I convert my object un

Answer 1

In addition to installing babel-jest (which comes with Jest by default now) be sure to install regenerator-runtime.

Answer 2

UPDATE 2020 - native support of ECMAScript modules (ESM)

---

According to this issue, there is native support of ESM from jest@25.4.0. So you won't have to use babel anymore. At the time of writing this answer (05/2020), to activate that you need to do three simple things:

• Make sure you don't transform away import statements by setting transform: {} in config file
• Run node@^12.16.0 || >=13.2.0 with --experimental-vm-modules flag
• Run your test with jest-environment-node or jest-environment-jsdom-sixteen.

So your Jest configuration file should contain at least this:

export default {
    testEnvironment: 'jest-environment-node',
    transform: {}
    ...
};

And to set --experimental-vm-modules flag, you will have to run Jest as follows:

node --experimental-vm-modules node_modules/jest/bin/jest.js

(I hope this will change in the future)

Answer 3

I encountered the same issue.

These are what I did:

yarn add --dev babel-jest @babel/core @babel/preset-env

Make file jest.config.js in rootDir.

module.exports = {
    moduleFileExtensions: ["js", "json", "jsx", "ts", "tsx", "json"],
    transform: {
        '^.+\\.(js|jsx)?$': 'babel-jest'
    },
    testEnvironment: 'node',
    moduleNameMapper: {
        '^@/(.*)$': '<rootDir>/$1'
    },
    testMatch: [
        '<rootDir>/**/*.test.(js|jsx|ts|tsx)', '<rootDir>/(tests/unit/**/*.spec.(js|jsx|ts|tsx)|**/__tests__/*.(js|jsx|ts|tsx))'
    ],
    transformIgnorePatterns: ['<rootDir>/node_modules/']
};

Then make file babal.config.js in rootDir.

Go like this:

module.exports = {
    "presets": ["@babel/preset-env"]
}

Answer 4

From my answer to another question, this can be simpler:

---

The only requirement is to configure your test environment to Babel, and add the ECMAScript 6 transform plugin:

---

Step 1:

Add your test environment to .babelrc in the root of your project:

{
  "env": {
    "test": {
      "plugins": ["@babel/plugin-transform-modules-commonjs"]
    }
  }
}

Step 2:

Install the ECMAScript 6 transform plugin:

npm install --save-dev @babel/plugin-transform-modules-commonjs

---

And that's it. Jest will enable compilation from ECMAScript modules to CommonJS automatically, without having to inform additional options to your jest property inside package.json.

Answer 5

It's a matter of adding stage-0 to your .babelrc file. Here is an example:

{
  "presets": ["es2015", "react", "stage-0"],
  "plugins": ["transform-decorators-legacy"]
}

Answer 6

I solved it with .default.

Try var Validation = require('../src/components/validation/validation').default;