开玩笑-TypeError：无法读取未定义的属性“项目”

Question

So I am starting to do unit testing of my React-Native application. I just wanted to try the first test and I immediately get errors.

Here is what my test looks like:

 import 'react-native'; import React from 'react'; import Index from '../index.ios.js'; // Note: test renderer must be required after react-native. import renderer from 'react-test-renderer'; it('renders correctly', () => { const tree = renderer.create( <Index /> ).toJSON(); expect(tree).toMatchSnapshot(); }); 

and here is my package JSON

 { "name": "project", "version": "0.0.1", "private": true, "scripts": { "start": "node node_modules/react-native/local-cli/cli.js start", "test": "jest", "build": "npm install && react-native link && react-native run-ios" }, "dependencies": { "anymatch": "^1.3.0", "native-base": "^2.2.0", "react": "16.0.0-alpha.12", "react-native": "0.45.1", "react-native-datepicker": "^1.6.0", "react-native-elements": "^0.13.0", "react-native-local-notifications": "^0.1.0", "react-native-maps": "^0.15.2", "react-native-notifications": "^1.1.11", "react-native-sound": "^0.10.3", "react-native-swipeout": "^2.1.3", "react-native-vector-icons": "^4.2.0", "react-navigation": "^1.0.0-beta.11", "react-redux": "^5.0.5", "redux": "^3.7.1", "redux-logger": "^3.0.6", "redux-thunk": "^2.2.0" }, "devDependencies": { "babel-jest": "20.0.3", "babel-preset-react-native": "2.0.0", "jest": "20.0.4", "react-test-renderer": "16.0.0-alpha.12" }, "jest": { "preset": "react-native" } } 

The error I get is this :

TypeError: Cannot read property 'projects' of undefined
at /Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/build/cli/runCLI.js:106:25
at Generator.next (<anonymous>)
at step (/Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/build/cli/runCLI.js:1:260)
at /Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/build/cli/runCLI.js:1:490
at Promise (<anonymous>)
at /Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/build/cli/runCLI.js:1:171
at module.exports (/Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/build/cli/runCLI.js:139:50)
at Object.run (/Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/build/cli/index.js:40:3)
at Object.<anonymous> (/Users/grantherman/Desktop/project/node_modules/jest/node_modules/jest-cli/bin/jest.js:14:25)
at Module._compile (module.js:569:30)

I literally have no idea why. I have looked around and no one has experienced the same error as this.

Answer 1

Under jest in your package.json , try adding "testEnvironment": "jsdom"

"jest": {
  "preset": "react-native",
  "testEnvironment": "jsdom"
}

Answer 2

I dont see jest-cli in your packages.json. I had the exact same issue with reactjs. Installing jest-cli (I only had jest) fixed the issue.