Swift 3.0 Error: Escaping closures can only capture inout parameters explicitly by value

Question

I\'m trying to update my project to Swift 3.0 but I have some difficulties. I\'m getting next error: \"Escaping closures can only capture inout parameters explicitly by valu

Answer 1

If you want to modify a variable passed by reference in an escaping closure, you can use KeyPath. Here is an example:

class MyClass {
    var num = 1
    func asyncIncrement(_ keyPath: WritableKeyPath) {
        DispatchQueue.main.async {
            // Use weak to avoid retain cycle
            [weak self] in
            self?[keyPath: keyPath] += 1
        }
    }
}

You can see the full example here.