Mock implementation incomplete?!

[jerone]

According to TypeScript typing, it looks like the Jest mock implementation delivered by this package is incomplete.

Using the following code (similar to the example in the docs):

import mockAsyncStorage from "@react-native-async-storage/async-storage/jest/async-storage-mock";
jest.mock<typeof import("@react-native-async-storage/async-storage")>(
  "@react-native-async-storage/async-storage",
  () => mockAsyncStorage,
);

This results in the following error:

Error log.

Argument of type '() => AsyncStorageStatic' is not assignable to parameter of type '() => typeof import("/node_modules/@react-native-async-storage/async-storage/lib/typescript/index")'.
  Type 'AsyncStorageStatic' is missing the following properties from type 'typeof import("/node_modules/@react-native-async-storage/async-storage/lib/typescript/index")': useAsyncStorage, AsyncStoragets(2345)

The work-around is to remove the typed mock, but I prefer not to do that:

-jest.mock<typeof import("@react-native-async-storage/async-storage")>( ... );
+jest.mock( ... );

I tried also to use Partial, but that gave a similar error:

jest.mock<Partial<typeof import("@react-native-async-storage/async-storage")>>( ... );

Does this count as a bug?

[jerone]

Still relevant.

[tamish-max]

This was a real pain point in older versions, but the current package is much better here.

In v3, the shipped Jest mock is fully typed and implements the AsyncStorage interface with an in-memory Map, so setup is straightforward:

// jest.setup.ts
jest.mock('@react-native-async-storage/async-storage', () =>
  require('@react-native-async-storage/async-storage/jest')
)

And if you want to isolate tests:

import { clearAllMockStorages } from '@react-native-async-storage/async-storage/jest'

afterEach(() => {
  clearAllMockStorages()
})

If you're still on v2, then yes, the mock typings can lag behind the real interface. In that case the cleanest fix is either:

• upgrade to the current release, or
• add a local typed wrapper around the mock until you can upgrade

So I would treat this as version-specific: older mock typings were incomplete, but current versions have largely fixed that problem.