Jest fails to run when node modules have es6 syntax (create-react-app)

Question

I have a create-react-app project and trying to unit test office-ui-fabric-react component using Jest and Enzyme.

The latest version of office-ui-fabric-react use es6 syntax and jest is failing to run the test.

import { mount } from "enzyme";
import React from "react";
import { MessageBar, MessageBarType } from "office-ui-fabric-react/lib/MessageBar";

describe("<MessageBar />", () => {
    it("renders message bar correctly", () => {
        const wrapper = mount(<MessageBar messageBarType={MessageBarType.success} />);
        expect(wrapper.find('.ms-MessageBar--success').length).toEqual(1);
    });
});

This is the package.json file coming from create-react-app with few additions

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "dependencies": {
    "office-ui-fabric-react": "^6.110.1",
    "react": "^16.6.3",
    "react-dom": "^16.6.3",
    "react-scripts": "2.1.1"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "devDependencies": {
    "@types/enzyme": "3.1.5",
    "@types/enzyme-adapter-react-16": "1.0.1",
    "@types/jest": "23.0.0",
    "@types/react": "16.3.16",
    "@types/react-dom": "16.0.5",
    "@types/react-test-renderer": "^16.0.0",
    "enzyme": "^3.7.0",
    "enzyme-adapter-react-16": "^1.7.0",
    "jest": "^23.6.0"
  }
}

Error

create-react-app is not allowing me to specify ani options for jest in package.json without ejecting.

Did npm install --save-dev babel-jest babel-core and it didn't work — user2133404
– user2133404, Commented Dec 5, 2018 at 2:14

user2133404 · Accepted Answer · 2018-12-05 06:54:30Z

-1

After looking at the suggestions in the comments above, the following set worked for me:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "dependencies": {
    "office-ui-fabric-react": "^6.110.1",
    "react": "^16.6.3",
    "react-dom": "^16.6.3",
    "react-scripts": "2.1.1"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "devDependencies": {
    "babel-core": "^7.0.0-bridge.0",
    "babel-jest": "^23.6.0",
    "enzyme": "^3.7.0",
    "enzyme-adapter-react-16": "^1.7.0",
    "jest": "^23.6.0"
  }
}

In my test file sample-tests.jsx

import Enzyme from "enzyme";
import { mount } from "enzyme";
import React from "react";
import { MessageBar, MessageBarType } from "office-ui-fabric-react/lib-commonjs/MessageBar";

import Adapter from 'enzyme-adapter-react-16';

Enzyme.configure({ adapter: new Adapter() });

describe("<MessageBar />", () => {
    it("renders message bar correctly", () => {
        const wrapper = mount(<MessageBar messageBarType={MessageBarType.success} />);
        expect(wrapper.find('.ms-MessageBar--success').length).toEqual(1);
    });
});

answered Dec 5, 2018 at 6:54

user2133404

1,8677 gold badges35 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Eric Haynes Over a year ago

None of this is necessary if using create-react-app. It supports jest with es modules out of the box. You should not add jest as a dependency in your own package.json at all; it's already done by react-scripts. Overriding that is not supported or recommended, and most likely broke the default behavior: stackoverflow.com/a/39932457/1057157

wereHamster Over a year ago

Your example works because you explicitly import the commonjs version of the package ("office-ui-fabric-react/lib-commonjs/MessageBar"). If you import { MessageBar } from "office-ui-fabric-react" then you likely get the same error.

Collectives™ on Stack Overflow

Jest fails to run when node modules have es6 syntax (create-react-app)

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related