Create a React Native custom module (with Swift)

Here is a quick and dirty example of how one can expose a custom module to React Native using Swift.

Product-Bridging-Header.h – Bridge header file

[code language=”C”]
#import "RCTBridgeModule.h"
[/code]

MySwiftThingy.m – Register Swift code with the React Native Bridge

[code language=”C”]
#import "RCTBridgeModule.h"

@interface RCT_EXTERN_MODULE(MySwiftThingy, NSObject)

RCT_EXTERN_METHOD(callbackMethod:(RCTResponseSenderBlock)callback)
RCT_EXTERN_METHOD(simpleMethod:(NSString *)message)

@end
[/code]

MySwiftThingy.swift – Custom Swift component

[code language=”Scala”]
import Foundation

@objc(MySwiftThingy)
class MySwiftThingy: NSObject {

@objc func callbackMethod(callback: RCTResponseSenderBlock) -> Void {
let resultsDict = [
"success" : true
];

callback([NSNull() ,resultsDict])
}

@objc func simpleMethod(message: String!) {
print("\(message)")
}
}
[/code]

Call it from JavaScript:

[code language=”JavaScript”]
const { MySwiftThingy } = require(‘NativeModules’);
MySwiftThingy.simpleMethod(‘hi’);
MySwiftThingy.callbackMethod((err,r) => console.log(r));
[/code]