Promise.all() for Independent Operations

Promise.all() for Independent Operations

Impact: CRITICAL (2-10x improvement on data loading)

When async operations have no interdependencies, execute them concurrently.

Incorrect (sequential, 3 round trips):

const user = await fetchUser()
const feed = await fetchFeed()
const notifications = await fetchNotifications()

Correct (parallel, 1 round trip):

const [user, feed, notifications] = await Promise.all([
  fetchUser(),
  fetchFeed(),
  fetchNotifications()
])

Common React Native cases:

• App startup: auth token + user profile + feature flags
• Screen mount: multiple API endpoints for a single screen
• Parallel AsyncStorage/MMKV reads
• Image prefetching alongside data fetching

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