mutate swift array from objc?

Question

Given the following class

@objc class Foo: NSObject {
  var myArray = [Bar]()
}

I'd like to add to array variable from objc.

Foo* foo = [[Foo alloc] init];
[foo.myArray addObject: bar];

myArray is typed as NSArray not NSMutableArray, so has no method addObject.

Answer 1

How about:

@objc class Foo: NSObject {
  var myArray = [Bar]()

  func addBar(newBar: Bar) {
    myArray.append(newBar)
  }
}

then

Foo* foo = [[Foo alloc] init];
[foo addBar: bar];

According to the Law of Demeter this is the better way to write it, as you're not accessing a method on a property of foo