TypeError: environment.setup is not a function in React Testing

Question

I was trying to implement the example shown in Jest website: Getting started with Jest.

While running npm test on I was getting the following error:

<

Answer 1

Add

"jest": {
    "testEnvironment": "node"
  }

to your package.json file, your package.json would look like this:

{
  "name": "jest-demo-test",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "react": "^16.2.0",
    "react-dom": "^16.2.0",
    "react-scripts": "1.0.17"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "jest",
    "eject": "react-scripts eject"
  },
  "devDependencies": {
    "jest": "^22.0.4"
  },
   "jest": {
    "testEnvironment": "node"
  }
}

---

UPDATE

for the people using create app and having this problem, there are two solutions.

1- update testcommand (or add new one) in package.json to jest instead of react-scripts test, because react-scripts test will not allow jest options in package.json as @Xinyang_Li stated in comments.

2-if you don't want to change test command in package.json, and use default create-react-app test; remove jest options from packge.json (if exists)

 "jest": {
    "testEnvironment": "node"
  }

then remove node_modules and then run npm install to install them all again, and after that your tests should run normally.