iOS Modules

Official Documentation

Steps:

• Create Custom Native Module Header.
• Create Corresponding Implementation file.
• Export Module To JavaScript.
• Test the Module from JavaScript.

Create Header File

Add a new Objective-C file to the project that implements the RCTBridgeModule protocol

#import <React/RCTBridgeModule.h>

@interface MyModule : NSObject <RCTBridgeModule>

@end

Create Module

#import "MyModule.h"

@implementation MyModule

// To export a module named MyModule
RCT_EXPORT_MODULE(MyModule);

RCT_EXPORT_METHOD(addNumbers:(int)number1
                  number2:(int)number2
                  resolver:(RCTPromiseResolveBlock)resolve
                  rejecter:(RCTPromiseRejectBlock)reject)
{
    int result = number1 + number2;
    resolve(@(result));
}

@end

Create a JavaScript interface

import { NativeModules } from 'react-native';

const { MyModule } = NativeModules;

MyModule.addNumbers(2, 3, (result) => {
    console.log(result); // prints 5
});