CODEWITHSUNDEEP
javascriptfirebasereact-nativejestjs
dennis-tra
dennis-tra

Reputation: 1319

Jest + Firebase: TypeError: Cannot read property 'defineProperties' of undefined

I'm currently working on an react native project and wanted to utilise the Firebase JS SDK. To get familiar with all it's API's I thought of writing some learning tests with Jest. This is my test:

import Firebase from 'firebase';
describe('Firebase', function() {
  it('should work', function() {
    expect(null).toBeNull()
  })
});

Unfortunately I'm getting this error: ● Test suite failed to run

TypeError: Cannot read property 'defineProperties' of undefined

  at node_modules/firebase/app-node.js:18:234
  at Object.<anonymous> (node_modules/firebase/app-node.js:23:260)
  at Object.<anonymous> (node_modules/firebase/firebase-node.js:8:16)
  at Object.<anonymous> (firebase.test.js:1:104)

If I replace the import state with import React from 'react' everything works fine. So why can't I use Firebase to test some API calls.

This is my package.json:

{
  ...,
  "dependencies": {
    "firebase": "^3.5.0",
    "react": "15.3.2",
    "react-native": "0.35.0"
  },
  "jest": {
    "preset": "jest-react-native"
  },
  "devDependencies": {
    "babel-jest": "16.0.0",
    "babel-preset-react-native": "1.9.0",
    "jest": "16.0.1",
    "jest-react-native": "16.0.0",
    "react-test-renderer": "15.3.2"
  }
}

Upvotes: 7

Views: 2542

Answers (1)

Benjamin H Boruff
Benjamin H Boruff

Reputation: 2969

The problem is that installing and configuring the "jest-react-native" and "react-native" presets breaks our ability to "import" firebase! The fix is to require firebase (not import) in your test.js file, and add a line that imports react-native. Without importing react-native in addition to require('firebase'), firebase will not be included in the test file! Here is my github repo that walks you through the steps that reproduce the error, and how to fix it.

There may also be a stale jest cache which may require you to run

./node_modules/jest/bin/jest.js --no-cach

This seems to happen everytime I change anything to do with a preprocessor option.

See jest documentation on caching issues.

Upvotes: 4

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