Check Cheap Conditions Before Async Work

Impact: HIGH (avoids unnecessary network/async calls)

When a branch requires both an async flag and a cheap synchronous condition, evaluate the cheap condition first. Otherwise you pay for the async call even when the result won’t be used.

Incorrect (always awaits):

const hasPermission = await checkPermission('camera')
if (hasPermission && Platform.OS === 'ios') {
  openIOSCamera()
}

Correct (cheap check first):

if (Platform.OS === 'ios') {
  const hasPermission = await checkPermission('camera')
  if (hasPermission) {
    openIOSCamera()
  }
}

Common React Native cases:

Platform.OS check before platform-specific async work
Feature flag check: skip network call if local condition is false
Auth state check before fetching protected resources
Empty input validation before API submission

Source: vercel-labs/agent-skills (MIT License)