Get reference to NSLayoutConstraint using Identifier set in storyboard

Question

I was setting the constraints of a button using a storyboard. I saw an option, \"Identifier\" in the constraint\'s properties.

Answer 1

Swift 3

I wrote a quick NSView extension which handles this nicely.

extension NSView {
    func constraint(withIdentifier: String) -> NSLayoutConstraint? {
        return self.constraints.filter { $0.identifier == withIdentifier }.first
    }
}

Usage:

if let c = button.constraint(withIdentifier: "my-button-width") {
    // do stuff with c
}