🍰 Layered Cakewalk [Swift] - Auto sizing UITextView where intrinsicContentSize reflects the text size.

UITextViewWithAutoLayout.swift

import UIKit

/// 
/// 🍰 Layered Cakewalk - UITextViewWithAutoLayout
///
/// A UITextView that has an `intrinsicContentSize` equal to the content size.
///

class UITextViewWithAutoLayout : UITextView
{
    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
    
        private var _observer: NSObjectProtocol?
        ///
    override init(frame: CGRect, textContainer: NSTextContainer?)
    {
        super.init(frame: frame, textContainer: textContainer)
        
        self.enablesReturnKeyAutomatically     = true
        self.backgroundColor                   = .clear
        self.layoutMargins                     = .zero
        self.insetsLayoutMarginsFromSafeArea   = false
        self.contentInset                      = .zero
        self.textContainerInset                = .zero
        self.textContainer.lineFragmentPadding = 0
        
        _observer = self.observe(\.contentSize, options: [.old, .new])
        {
            view, change in
            
            if change.oldValue != change.newValue
            {
                view.invalidateIntrinsicContentSize()
            }
        }
    }
    
    override var intrinsicContentSize: CGSize
    {
        self.contentSize
    }
}