Get height for constrained width string.

heightWithConstrainedWidth.swift

extension String {
  func heightWithConstrainedWidth(_ width: CGFloat, font: UIFont) -> CGFloat {
    let constraintRect = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
    let boundingBox = (self as NSString).boundingRect(with: constraintRect,
                                                   options: .usesLineFragmentOrigin,
                                                attributes: [NSFontAttributeName: font],
                                                   context: nil)
    return boundingBox.height
  }
}