Permission Handler

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Recipe: working around stale permission state on Expo cold start ​

Problem. Expo Managed Workflow apps that use Location.getBackgroundPermissionsAsync() (or any expo-location permission hook) may observe stale undetermined status on app restart: the first call returns undetermined even when the true status is denied, and subsequent calls return the correct value a moment later. This races with any if (status === "undetermined") gate in your app logic.

Source: expo/expo#42084 — Expo's location hook caches the last-seen value across process boundaries, and the initial stale read races the fresh system check.

Solution. Wrap the permission in usePermissionHandler with recheckOnForeground: true. The library calls engine.check() directly (bypassing Expo's hook cache) and the recheckOnForeground flag ensures any foreground transition re-runs the check. The hook's autoCheck: true (default) also runs a fresh check on mount — which is the fix for the cold-start stale read.

What you'll use ​

  • usePermissionHandler — the hook calls engine.check(permission) on mount, which hits the native module directly and avoids Expo's hook-level cache.
  • createExpoEngine — Expo engine with auto-discovered expo-location module.
  • recheckOnForeground: true — belt-and-braces foreground recheck for long-lived sessions.

Minimal example ​

tsx
import { useMultiplePermissions, usePermissionHandler } from "react-native-permission-handler";
import { createExpoEngine } from "react-native-permission-handler/expo";

const engine = createExpoEngine();

function LocationGate() {
  // On cold start, autoCheck hits engine.check("locationBackground") directly.
  // The library's hook does not go through Expo's useForegroundPermissions /
  // useBackgroundPermissions hooks, so the stale-cache race from Expo #42084
  // does not apply.
  const location = usePermissionHandler({
    engine,
    permission: "locationBackground",
    recheckOnForeground: true,
    prePrompt: {
      title: "Background location",
      message: "We keep tracking your run when the screen is off.",
    },
    blockedPrompt: {
      title: "Background location blocked",
      message: "Enable 'Always Allow' location in Settings.",
    },
  });

  if (location.isGranted) return <RunTracker />;
  return <LocationPrompt handler={location} />;
}

Why this works ​

Expo's own permission hooks (e.g. Location.useBackgroundPermissions()) maintain module-level state that can outlive a process and be re-read on the next cold start before the native layer responds. This library's hooks never touch that cache: every check() and request() call resolves through the engine adapter, which calls the native Expo function directly. A fresh result always reflects the actual system status.

The trade-off: you pay one extra native round-trip on mount (vs. Expo's cached hook returning immediately). In practice this is imperceptible and the correctness win is worth it — stale undetermined reads have cost Expo developers real production bugs.

Combining with recheckOnForeground ​

Even without the Expo bug, long-lived screens benefit from re-checking on foreground return in case the user toggled the permission in Settings mid-session. See the recheck-on-foreground recipe for the full semantics.

See also ​