Use NSProxy in Swift

How to create an NSProxy subclass in Swift?

Trying to add any of the init methods fails with error: "Super init can't be called outside of the initializer", or "Super init isn't called on all paths before returning from initializer"

Using Objective-C subclass as a Base class works, but feels more like a hack:

// Create a base class to use instead of `NSProxy`
@interface WorkingProxyBaseClass : NSProxy
- (instancetype)init;
@end

@implementation WorkingProxyBaseClass
- (instancetype)init
{
  if (self) {

  }
  return self;
}
@end



// Use the newly created Base class to inherit from in Swift
import Foundation

class TestProxy: WorkingProxyBaseClass {
  override init() {
    super.init()
  }
}

Simple solution: make Objective-C class that inherits from NSProxy and then inherit Swift class from it.

Example at my GitHub: https://gist.github.com/SoundBlaster/0e53bae4ab814537c5868564d95eb553

// Objective-C Header BaseProxyForSwift.h

NS_ASSUME_NONNULL_BEGIN

NS_SWIFT_NAME(BaseProxyForSwift)
@interface BaseProxyForSwift : NSProxy

+ (id)with:(id)object;

@end

NS_ASSUME_NONNULL_END

// Objective-C Implementation BaseProxyForSwift.m

#import "BaseProxyForSwift.h"

@interface BaseProxyForSwift ()
@property (nonatomic, strong) id object;
@end

@implementation BaseProxyForSwift

+ (id)with:(id)object {
    BaseProxyForSwift *res = [self alloc];
    res.object = object;
    return res;
}

@end

// Swift Implementation BaseSwiftProxy.swift

import Foundation

public class BaseSwiftProxy: BaseProxyForSwift {}

// Usage in Swift

let a = NSObject()
let p = BaseSwiftProxy.with(a)

Don't forget about Objective-C Bridging Headers if you will mix languages in one project: https://developer.apple.com/documentation/swift/importing-objective-c-into-swift.