iOS AutoLayout Extensions with NSLayoutAnchor

UIView+Constraints.swift

// MARK - UIView + Constraints

extension UIView {

    @discardableResult func topAnchor(equalTo anchor: NSLayoutYAxisAnchor, constant: CGFloat = 0) -> Self {
        topAnchor.constraint(equalTo: anchor, constant: constant).isActive = true
        return self
    }

    @discardableResult func bottomAnchor(equalTo anchor: NSLayoutYAxisAnchor, constant: CGFloat = 0) -> Self {
        bottomAnchor.constraint(equalTo: anchor, constant: constant).isActive = true
        return self
    }

    @discardableResult func leadingAnchor(equalTo anchor: NSLayoutXAxisAnchor, constant: CGFloat = 0) -> Self {
        leadingAnchor.constraint(equalTo: anchor, constant: constant).isActive = true
        return self
    }

    @discardableResult func trailingAnchor(equalTo anchor: NSLayoutXAxisAnchor, constant: CGFloat = 0) -> Self {
        trailingAnchor.constraint(equalTo: anchor, constant: constant).isActive = true
        return self
    }

    @discardableResult func heightAnchor(equalTo height: CGFloat) -> Self {
        heightAnchor.constraint(equalToConstant: height).isActive = true
        return self
    }

    @discardableResult func widthAnchor(equalTo height: CGFloat) -> Self {
        widthAnchor.constraint(equalToConstant: height).isActive = true
        return self
    }

}

// MARK - Example
var label = UILabel(frame: .zero)
phoneLabel
  .topAnchor(equalTo: otherLabel.bottomAnchor, constant: defaultMargin)
  .leadingAnchor(equalTo: leadingAnchor, constant: defaultMargin)
  .trailingAnchor(equalTo: trailingAnchor, constant: defaultMargin)