Over-the-air updates (EAS Update) in React Native - Build, Publish & Deploy

Build & Publish - Over-the-air updates (EAS Update)

Performance Impact

Using EAS Update allows your React Native app to receive code and asset updates instantly without waiting for app store approval. This keeps your app fresh and responsive. However, downloading updates in the background can use network data and CPU, so it is important to manage update size and frequency to avoid slowing down the app or draining battery.

Optimization Tips

To keep your app running smoothly at 60fps, limit the size of each update by only changing necessary files. Use differential updates to send only changed code. Schedule updates to download when the device is idle or on Wi-Fi to reduce impact. Also, test updates thoroughly to avoid runtime errors that can cause crashes or freezes.

App Bundle Size and Startup Time

EAS Update does not increase your initial app bundle size because updates are delivered after install. This means your app starts quickly from the store. However, large or frequent updates can increase storage use over time. Clean up unused assets and code in updates to keep storage use minimal and startup fast.

iOS vs Android Differences

Both iOS and Android support EAS Update for React Native apps, but iOS requires strict code signing and app store rules. Apple allows over-the-air updates only for JavaScript and assets, not native code changes. Android is more flexible but still requires signed APKs or AABs for native code. EAS Update handles these rules by updating only JS and assets, ensuring compliance on both platforms.

Store Review Guidelines

• Apple App Store requires that over-the-air updates do not change the app's primary functionality or native code.
• Updates must comply with Apple's App Store Review Guidelines, especially sections on code execution and security.
• Google Play allows JS and asset updates but native code changes require a new APK/AAB submission.
• Ensure your update mechanism does not violate user privacy or security policies.
• Provide clear user communication if updates require app restarts or affect app behavior.

Self-Check

Your app takes 5 seconds to load this screen after an update. What's likely wrong?

• The update package is too large, causing slow download or processing.
• Update is applied synchronously on app start, blocking UI rendering.
• Unoptimized assets or code in the update increase load time.
• Network conditions delay update download and installation.

To fix, reduce update size, apply updates asynchronously, and test on slow networks.

Key Result

EAS Update enables fast, store-independent delivery of JavaScript and asset updates for React Native apps, improving user experience by reducing app store wait times. Proper update size management and compliance with platform rules ensure smooth performance and successful store reviews.

Practice

1.

What is the main benefit of using Over-the-air (OTA) updates with EAS Update in a React Native app?

easy

A. Fix bugs and add features without waiting for app store approval

B. Increase app size by adding more assets

C. Require users to reinstall the app for every update

D. Disable app functionality temporarily during updates

Solution

1. Step 1: Understand OTA update purpose

   OTA updates let developers fix bugs and add features quickly without app store delays.

2. Step 2: Compare options

   Only Fix bugs and add features without waiting for app store approval describes this benefit correctly; others describe drawbacks or unrelated effects.

3. Final Answer:

   Fix bugs and add features without waiting for app store approval -> Option A

4. Quick Check:

   OTA updates = fast fixes and features [OK]

Hint: OTA updates = fast fixes without app store wait [OK]

Common Mistakes:

• Thinking OTA updates increase app size
• Believing users must reinstall app for OTA
• Assuming app disables during update

2.

Which of the following is the correct way to import the Expo Updates API in a React Native app?

?

easy

A. import { Updates } from 'expo';

B. import Updates from 'react-native-updates';

C. const Updates = require('expo-updates');

D. import * as Updates from 'expo-updates';

Solution

1. Step 1: Recall Expo Updates import syntax

   The official Expo Updates API is imported using "import * as Updates from 'expo-updates';".

2. Step 2: Check other options

   Options A, B, and C use incorrect package names or import styles not recommended for Expo Updates.

3. Final Answer:

   import * as Updates from 'expo-updates'; -> Option D

4. Quick Check:

   Correct import = import * as Updates from 'expo-updates'; [OK]

Hint: Expo Updates import uses * as Updates from 'expo-updates' [OK]

Common Mistakes:

• Using wrong package name like 'react-native-updates'
• Using require instead of import
• Importing Updates from 'expo' instead of 'expo-updates'

3.

Given this React Native code snippet using Expo Updates API, what will be logged if an update is available?

import * as Updates from 'expo-updates';

async function checkUpdate() {
  const update = await Updates.checkForUpdateAsync();
  if (update.isAvailable) {
    console.log('Update found!');
  } else {
    console.log('No update available.');
  }
}

checkUpdate();

medium

A. SyntaxError

B. No update available.

C. Update found!

D. Nothing is logged

Solution

1. Step 1: Analyze checkForUpdateAsync result

   The function returns an object with isAvailable true if an update exists.

2. Step 2: Follow the if condition

   If update.isAvailable is true, it logs 'Update found!'. Otherwise, logs 'No update available.'

3. Final Answer:

   Update found! -> Option C

4. Quick Check:

   Update available logs 'Update found!' [OK]

Hint: If update.isAvailable true, logs 'Update found!' [OK]

Common Mistakes:

• Confusing checkForUpdateAsync return value
• Expecting syntax error from async function
• Thinking nothing logs without await

4.

Identify the error in this code snippet that tries to fetch and reload an update using Expo Updates API:

import * as Updates from 'expo-updates';

async function updateApp() {
  const update = Updates.checkForUpdateAsync();
  if (update.isAvailable) {
    await Updates.fetchUpdateAsync();
    Updates.reloadAsync();
  }
}

medium

A. reloadAsync() must be called before fetchUpdateAsync()

B. Missing await before Updates.checkForUpdateAsync()

C. fetchUpdateAsync() should not be awaited

D. No error, code is correct

Solution

1. Step 1: Check async function usage

   Updates.checkForUpdateAsync() returns a Promise and must be awaited to get the result.

2. Step 2: Identify missing await impact

   Without await, update is a Promise, so update.isAvailable is undefined causing error.

3. Final Answer:

   Missing await before Updates.checkForUpdateAsync() -> Option B

4. Quick Check:

   Always await async calls to get results [OK]

Hint: Always await async calls like checkForUpdateAsync() [OK]

Common Mistakes:

• Forgetting await on async functions
• Calling reloadAsync() before fetching update
• Assuming fetchUpdateAsync() is synchronous

5.

You want your React Native app to check for OTA updates on app start, download them silently, and apply on next app reload. Which approach correctly implements this behavior?

?

hard

A. Use Updates.checkForUpdateAsync(), then if available, call Updates.fetchUpdateAsync() without reload, apply on next start

B. Call Updates.reloadAsync() immediately on app start to force update

C. Only call Updates.fetchUpdateAsync() without checking availability

D. Use Updates.checkForUpdateAsync() and reloadAsync() immediately without fetching

Solution

1. Step 1: Understand OTA update flow

   Check for update availability first, then fetch update silently if available.

2. Step 2: Apply update on next reload

   Fetching update downloads it; reloadAsync applies update immediately, but we want to apply on next app start.

3. Final Answer:

   Use Updates.checkForUpdateAsync(), then if available, call Updates.fetchUpdateAsync() without reload, apply on next start -> Option A

4. Quick Check:

   Check, fetch silently, reload later = Use Updates.checkForUpdateAsync(), then if available, call Updates.fetchUpdateAsync() without reload, apply on next start [OK]

Hint: Check availability, fetch silently, reload later for smooth update [OK]

Common Mistakes:

• Reloading app immediately causing bad UX
• Fetching update without checking availability
• Reloading without fetching update