Turbo Modules overview in React Native

Introduction

Turbo Modules make React Native apps faster by improving how native code and JavaScript talk to each other.

When you want your app to load and run faster.

When you need smoother animations or quicker responses.

When your app uses a lot of native features and you want better performance.

When you want to reduce delays caused by communication between JavaScript and native code.

Syntax

React Native

export default TurboModuleRegistry.getEnforcing<Spec>('ModuleName');

Turbo Modules use a special registry to load native modules efficiently.

You define the native module interface in TypeScript or Objective-C/Java and access it via TurboModuleRegistry.

Examples

This example shows how to get a Turbo Module named 'MyModule' in React Native.

React Native

import {TurboModuleRegistry} from 'react-native';

const MyModule = TurboModuleRegistry.getEnforcing<MyModuleSpec>('MyModule');

Here we define the module's methods in TypeScript and then get the module instance.

React Native

interface MyModuleSpec {
  multiply(a: number, b: number): number;
}

const MyModule = TurboModuleRegistry.getEnforcing<MyModuleSpec>('MyModule');

Sample App

This React Native app uses a Turbo Module called 'MathModule' to multiply two numbers. When you press the button, it calls the native multiply method and shows the result.

React Native

import React from 'react';
import {Button, Text, View} from 'react-native';
import {TurboModuleRegistry} from 'react-native';

interface MathModuleSpec {
  multiply(a: number, b: number): number;
}

const MathModule = TurboModuleRegistry.getEnforcing<MathModuleSpec>('MathModule');

export default function App() {
  const [result, setResult] = React.useState<number | null>(null);

  const handleMultiply = () => {
    const res = MathModule.multiply(3, 4);
    setResult(res);
  };

  return (
    <View style={{flex: 1, justifyContent: 'center', alignItems: 'center'}}>
      <Button title="Multiply 3 x 4" onPress={handleMultiply} />
      {result !== null && <Text>Result: {result}</Text>}
    </View>
  );
}

Important Notes

Turbo Modules improve app speed by reducing the time to call native code.

They require native code setup in Objective-C/Swift for iOS and Java/Kotlin for Android.

Turbo Modules are part of React Native's new architecture for better performance.

Summary

Turbo Modules speed up communication between JavaScript and native code.

Use TurboModuleRegistry to access native modules efficiently.

This helps make React Native apps faster and smoother.

Practice

1. What is the main purpose of Turbo Modules in React Native?

easy

A. To speed up communication between JavaScript and native code

B. To create UI components faster

C. To manage app navigation

D. To handle network requests

Solution

1. Step 1: Understand Turbo Modules role

   Turbo Modules are designed to improve the speed of interaction between JavaScript and native code in React Native apps.

2. Step 2: Compare with other options

   Creating UI components, managing navigation, and handling network requests are not the primary goals of Turbo Modules.

3. Final Answer:

   To speed up communication between JavaScript and native code -> Option A

4. Quick Check:

   Turbo Modules = Faster JS-native communication [OK]

Hint: Turbo Modules speed up JS and native code talking [OK]

Common Mistakes:

• Confusing Turbo Modules with UI components
• Thinking Turbo Modules handle navigation
• Assuming Turbo Modules manage network

2. Which of the following is the correct way to access a Turbo Module named MyModule in React Native?

easy

A. const myModule = ModulesRegistry.get('MyModule');

B. const myModule = NativeModules.get('MyModule');

C. const myModule = TurboModule.get('MyModule');

D. const myModule = TurboModuleRegistry.get('MyModule');

Solution

1. Step 1: Recall correct API usage

   The official way to access Turbo Modules is using TurboModuleRegistry.get('ModuleName').

2. Step 2: Eliminate incorrect options

   NativeModules.get and TurboModule.get are not valid methods. ModulesRegistry does not exist.

3. Final Answer:

   const myModule = TurboModuleRegistry.get('MyModule'); -> Option D

4. Quick Check:

   Use TurboModuleRegistry.get() to access Turbo Modules [OK]

Hint: Use TurboModuleRegistry.get('Name') to access modules [OK]

Common Mistakes:

• Using NativeModules instead of TurboModuleRegistry
• Calling non-existent get methods
• Mixing up module registry names

3. What will happen if you try to access a Turbo Module that does not exist using TurboModuleRegistry.get('UnknownModule')?

medium

A. It returns null or undefined

B. It throws a syntax error

C. It crashes the app immediately

D. It returns an empty object

Solution

1. Step 1: Understand TurboModuleRegistry behavior

   If the requested module does not exist, TurboModuleRegistry.get() returns null or undefined instead of throwing errors.

2. Step 2: Check other options

   No syntax error or immediate crash occurs. It does not return an empty object either.

3. Final Answer:

   It returns null or undefined -> Option A

4. Quick Check:

   Missing Turbo Module returns null/undefined [OK]

Hint: Missing Turbo Modules return null or undefined [OK]

Common Mistakes:

• Expecting a syntax error
• Assuming app crashes immediately
• Thinking it returns empty object

4. You wrote const myModule = TurboModuleRegistry.get('MyModule') but get an error saying TurboModuleRegistry is not defined. What is the likely cause?

medium

A. Turbo Modules are not supported on your device

B. You misspelled the module name in get()

C. You forgot to import TurboModuleRegistry from 'react-native'

D. You need to call TurboModuleRegistry as a function

Solution

1. Step 1: Analyze the error message

   The error TurboModuleRegistry is not defined means the variable or object is not available in the current scope.

2. Step 2: Identify common cause

   This usually happens if you forget to import TurboModuleRegistry from the React Native package.

3. Final Answer:

   You forgot to import TurboModuleRegistry from 'react-native' -> Option C

4. Quick Check:

   Missing import causes 'not defined' error [OK]

Hint: Always import TurboModuleRegistry before use [OK]

Common Mistakes:

• Assuming misspelled module name causes 'not defined'
• Thinking device support causes 'not defined'
• Trying to call TurboModuleRegistry as a function

5. You want to improve your React Native app's performance by using Turbo Modules. Which of the following steps should you take to correctly implement and access a Turbo Module named FastLogger?

hard

A. Use NativeModules.FastLogger without any native Turbo Module implementation

B. Implement native code for FastLogger, export it as a Turbo Module, then access it via TurboModuleRegistry.get('FastLogger')

C. Write FastLogger only in JavaScript and import it normally

D. Create FastLogger as a React component and use it in JSX

Solution

1. Step 1: Understand Turbo Module implementation

   Turbo Modules require native code implementation and exporting as a Turbo Module to gain performance benefits.

2. Step 2: Access Turbo Module correctly

   After native implementation, access the module in JavaScript using TurboModuleRegistry.get('FastLogger').

3. Step 3: Eliminate incorrect options

   Writing only JavaScript or using NativeModules without Turbo Module native code won't improve performance. Creating a React component is unrelated.

4. Final Answer:

   Implement native code for FastLogger, export it as a Turbo Module, then access it via TurboModuleRegistry.get('FastLogger') -> Option B

5. Quick Check:

   Native Turbo Module + TurboModuleRegistry.get() = Performance boost [OK]

Hint: Native code + TurboModuleRegistry.get() = Turbo Module use [OK]

Common Mistakes:

• Skipping native implementation
• Using NativeModules instead of TurboModuleRegistry
• Confusing Turbo Modules with React components