expo: Expo 31 Jest transform error repro in tabs project template

Expo CLI 2.2.5

expo init expo-31-project, choose tabs
rm -rf node_modules && npm i
npx jest
Jest error:

Jest encountered an unexpected token

expo-31-project/node_modules/expo/build/environment/logging.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import { Constants } from 'expo-constants';

SyntaxError: Unexpected token {
      at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:403:17)
      at Object.<anonymous> (node_modules/expo/build/Expo.js:284:1)

About this issue

Original URL
State: closed
Created 6 years ago
Reactions: 1
Comments: 23 (5 by maintainers)

Commits related to this issue

Uninstall jest and babel-jest jest and babel-jest are unnecessary when using jest-expo https://github.com/expo/expo/issues/2595#issuecomment-440966998 — committed to joeyschroeder/expo-react-native-redux-starter by joeyschroeder 6 years ago
Amplify and Jest Sample Add a new emptyish Expo app to demonstrate Amplify and Jest not playing well together with (mostly) out of the box settings. Includes the workaround for issue [expo/expo#2595... — committed to josephbridgwaterrowe/amplify-and-jest-sample by josephbridgwaterrowe 5 years ago
Amplify and Jest Sample Add a new emptyish Expo app to demonstrate Amplify and Jest not playing well together with (mostly) out of the box settings. Includes the workaround for issue https://github.... — committed to josephbridgwaterrowe/amplify-and-jest-sample by josephbridgwaterrowe 5 years ago
Amplify and Jest Sample Add a new emptyish Expo app to demonstrate Amplify and Jest not playing well together with (mostly) out of the box settings. Includes the workaround for issue https://github.... — committed to josephbridgwaterrowe/amplify-and-jest-sample by josephbridgwaterrowe 5 years ago
Amplify and Jest Sample Add a new emptyish Expo app to demonstrate Amplify and Jest not playing well together with (mostly) out of the box settings. Includes the workaround for issue https://github.... — committed to josephbridgwaterrowe/amplify-and-jest-sample by josephbridgwaterrowe 5 years ago

Most upvoted comments

Thanks @artyorsh for sharing, unfortunately your repo might be a bit confusing for someone that doesn’t want all the typescript stuff, as that is a significant part of your jest configuration.

The only thing that actually seems to be needed is:

installed jest-expo (not jest!) jest.config.js file:

module.exports = {
  preset: 'jest-expo',
  transform: {
    '\\.js$': '<rootDir>/node_modules/react-native/jest/preprocessor.js',
  }
};

leave the babel.config.js the way it was

@Overtorment @metz0r Please try and let me know if that helps.

My package.json:

{
  "name": "empty-project-template",
  "main": "node_modules/expo/AppEntry.js",
  "private": true,
  "scripts": {
    "start": "expo start",
    "android": "expo start --android",
    "ios": "expo start --ios",
    "eject": "expo eject",
    "test": "jest"
  },
  "dependencies": {
    "expo": "^31.0.2",
    "react": "16.5.0",
    "react-native": "https://github.com/expo/react-native/archive/sdk-31.0.0.tar.gz"
  },
  "devDependencies": {
    "babel-preset-expo": "^5.0.0",
    "jest-expo": "^31.0.0"
  }
}

+52

lgandecki on Nov 22, 2018

Still having this issue even after creating a brand new project with tabs using expo.

npm version: 6.2.0 node version: 10.9.0

See image

cmacdonnacha on Mar 2, 2019

@bruno-edo answered my question here. The basic gist is use yarn instead of npm. Seems like the Expo dev’s didn’t test their code with npm and npm messes things up.

janhesters on Feb 14, 2019

@c316 Thank you for bringing that up. I updated the original comment with my approach to using the workaround: https://github.com/expo/expo/issues/2595#issuecomment-443193112

freeatnet on Dec 12, 2018

@freeatnet it isn’t clear how to use that workaround. Can you post some more information on how to implement that workaround?

rootedsoftware on Dec 12, 2018

Hey! It looks like npm installs different dependencies versions than yarn, try installing deps with yarn. 🙂

sjchmiela on Nov 5, 2018