Got “is not a recognized Objective-C method” when bridging Swift to React-Native

Question

I\'m trying to bridge my React-Native 0.33 code to a super simple Swift method, following this guide but all I\'m getting is show:(NSString *)name is not a recognized

Answer 1

This is a part of Swift 3's changes and can be solved by adding an underscore:

import Foundation

@objc(SwitchManager)
class SwitchManager: NSObject {

  @objc func show(_ name: String) {
    NSLog("%@", name);
  }

}

See Swift 3's 0046 Proposal: Establish consistent label behavior across all parameters including first labels that is called out in the Swift.org migration guide under "Consistent first argument labels".

Basically, how Objective-C sees Swift methods has changed with Swift 3.

EDIT: This is still the case in Swift 4, see docs here under Omitting Argument Labels.