Fix Expo tokenCache

[devchampian]

Type of change

• 🐛 Bug fix
• 🌟 New feature
• 🔨 Breaking change
• 📖 Refactoring / dependency upgrade / documentation
• other:

Packages affected

• @clerk/clerk-js
• @clerk/clerk-react
• @clerk/nextjs
• @clerk/types
• @clerk/clerk-expo
• @clerk/backend-core
• @clerk/clerk-sdk-node
• @clerk/edge
• build/tooling/chore

Description

• ⛔️ npm test runs as expected.
• ⛔️ npm run build runs as expected.

☝️ Both are failing but unrelated to my changes. The build succeeds for clerk-expo package without errors.

This fix does two things.

The first is add a guard to check for the existence of tokenCache.getToken and tokenCache.saveToken. Previously, if a tokenCache was passed in, but had different methods on it, e.g. get / set, it would attempt to call undefined functions instead of falling back to the getTokenFromMemory and saveTokenInMemory operations, which are sensible defaults.

The second change here adds an early return if the tokenCache is not provided at all. This makes an assumption that the token cache is not available for the web platform, which is the case with expo-secure-store that is being used in our clerk-expo-starter.

Ideally, we should do better detection of the platform instead of coupling the logic with the tokenCache. One option would be to use Platform.OS === 'web' provided by react-native itself, but that introduces react-native as a package dependency.

This fix, coupled with changes I recently made to the clerk-expo-starter, allow the starter to render on the web without additional changes. It also means we could potentially remove or update this banner in the Docs:

[SokratisVidros]

💯