Denied permissions do not crash the app

An unhandled promise rejection from a permission-gated API call causes a visible red screen in development and a silent crash in production — neither outcome is acceptable. CWE-391 (Unchecked Error Condition) and CWE-755 (Improper Handling of Exceptional Conditions) directly describe this pattern. Apps that call Geolocation.getCurrentPosition(), Contacts.getAll(), or Camera.takePicture() without a preceding permission check assume the permission is permanently granted — but users can revoke permissions mid-session in iOS and Android Settings. The revocation takes effect immediately: the next call to the native API will fail with an authorization error, and if the call is not wrapped in a try-catch, the app crashes. This is the leading cause of crash loops reported after users update their privacy settings.

Wrap every protected API call in a try-catch and check permission status before the call. Never assume a previously granted permission is still in effect.

import { check, PERMISSIONS, RESULTS } from 'react-native-permissions'
import Geolocation from '@react-native-community/geolocation'

async function getCurrentLocation(): Promise<{ lat: number; lng: number } | null> {
  try {
    const status = await check(
      Platform.OS === 'ios'
        ? PERMISSIONS.IOS.LOCATION_WHEN_IN_USE
        : PERMISSIONS.ANDROID.ACCESS_FINE_LOCATION
    )
    if (status !== RESULTS.GRANTED) {
      return null // Feature degrades gracefully
    }
    return await new Promise((resolve, reject) =>
      Geolocation.getCurrentPosition(
        pos => resolve({ lat: pos.coords.latitude, lng: pos.coords.longitude }),
        reject,
        { timeout: 5000 }
      )
    )
  } catch (error) {
    console.warn('Location unavailable:', error)
    return null // Never throw — callers receive null and handle accordingly
  }
}