constrainToEdges, constrain

constrainToEdges.swift

extension UIView {

    @discardableResult
    func constrain(constraints: (UIView) -> [NSLayoutConstraint]) -> [NSLayoutConstraint] {
        let constraints = constraints(self)
        self.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate(constraints)
        return constraints
    }

    @discardableResult
    func constrainToEdges(_ inset: UIEdgeInsets = .zero) -> [NSLayoutConstraint] {
		constrain {
			guard let superview = $0.superview else { return [] }
			return [
				$0.topAnchor.constraint(equalTo: superview.topAnchor, constant: inset.top),
				$0.leadingAnchor.constraint(equalTo: superview.leadingAnchor, constant: inset.left),
				$0.bottomAnchor.constraint(equalTo: superview.bottomAnchor, constant: inset.bottom),
				$0.trailingAnchor.constraint(equalTo: superview.trailingAnchor, constant: inset.right)
			]
		}
    }
    
}