Bug: Mocks broken for plain JS projects

[janhesters]

Current behavior

When you follow the docs on how to integrate this module with Jest in a plain JS project, tests don't run. The reason is that the mock code references Flow types.

  ● Test suite failed to runmponent.test.js

    /Users/jan/dev/app/node_modules/@react-native-community/async-storage/jest/async-storagemock.js: 6
    type KeysType = Array<string>;
         ^^^^^^^^

    SyntaxError: Unexpected identifier

See also discussion in #39.

Expected behavior

The mock should work for projects that avoid static types.

Repro steps

1. Create a project without static types (e.g. npx react-native init myproject) and install AsyncStorage
2. In your project root directory, create __mocks__/@react-native-community directory.
3. Inside that folder, create async-storage.js file.
4. Inside that file, export Async Storage mock.
5. Run a test that uses AsyncStorage

export default from '@react-native-community/async-storage/jest/async-storage-mock'

Environment

• Async Storage version: 1.6.2
• React-Native version: 0.61.3
• Platform tested: None -> It's in Jest tests
• Logs/Error that are relevant: see Actual behavior

[krizzu]

@janhesters Whole project uses Flow, not only the Mock implementation. What preset do you use in your jest tests?

[janhesters]

@krizzu Here is my Jest config:

  "jest": {
    "preset": "@testing-library/react-native",
    "setupFilesAfterEnv": [
      "@testing-library/react-native/cleanup-after-each"
    ],
    "moduleDirectories": [
      "node_modules",
      "utils"
    ]
  }

[krizzu]

@janhesters What about babel.config.js? @testing-library/react-native uses react-native preset, which relies on babel module:metro-react-native-babel-preset preset to parse flow in RN app.

[krizzu]

@janhesters any update for this?

[janhesters]

@krizzu babel.config.js is:

module.exports = {
  presets: ['module:metro-react-native-babel-preset'],
};

[krizzu]

Have you tried the step from troubleshooting docs?

[iamolegga]

Same issue, with same babel config.

@krizzu there is another error text , and it did not help

[krizzu]

@iamolegga what error text you see?

[iamolegga]

The same as topic starter

[krizzu]

I'd need more context then, like your Jest setup. Example app is a good place to lookup the config, if you need it.

[krizzu]

Addressed already, mocks are type-free now