Access container view child properties swift

Question

What I want to achieve:

User presses the button in the ViewController then, the color of the button placed in the container view should change its color to red.

Answer 1

I recommend not to rely on segue.identifier, but rather test for destination type directly:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    super.prepare(for: segue, sender: sender)

    if let vc = segue.destination as? YourViewController {
        vc.someVariable = true
    }
}

This way you avoid mistakes with a misspelled segue name.