UITextView with some commonly needed additions

TestView.swift

import UIKit

open class TextView: UITextView {
    // MARK: - Public Properties
    public var autoSizing: Bool = false {
        didSet { redraw() }
    }
    public var minimumLines: Int = 1 {
        didSet { redraw() }
    }
    public var maximumLines: Int = 10 {
        didSet { redraw() }
    }
    public var placeholderText: String? = "" {
        didSet { redraw() }
    }
    public var placeholderTextFont: UIFont? {
        didSet { redraw() }
    }
    public var placeholderTextColor: UIColor = .lightGray {
        didSet { redraw() }
    }

    // MARK: - Private Properties
    private lazy var placeholderLabel: UILabel = {
        let label = UILabel()
        label.backgroundColor = .clear
        insertSubview(label, at: 0)
        return label
    }()
    
    public override init(frame: CGRect, textContainer: NSTextContainer?) {
        super.init(frame: frame, textContainer: textContainer)
        configure()
    }
    public required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        configure()
    }
    private func configure() {
        NotificationCenter.default.addObserver(self, selector: #selector(redraw), name: UITextView.textDidChangeNotification, object: self)
        
        redraw()
    }
    open override func layoutSubviews() {
        super.layoutSubviews()
        
        let x = textContainer.lineFragmentPadding
        let y = textContainerInset.top
        let width = bounds.width - (x * 2)
        let height = placeholderLabel.font!.lineHeight

        placeholderLabel.frame = CGRect(
            x: x, y: y,
            width: width, height: height
        )
    }
    
    // MARK: - Private Functions
    @objc private func redraw() {
        invalidateIntrinsicContentSize()
        
        placeholderLabel.text = placeholderText
        placeholderLabel.font = placeholderTextFont ?? font
        placeholderLabel.textColor = placeholderTextColor
        placeholderLabel.isHidden = placeholderText == nil || !text.isEmpty
    }
    
    // MARK: - Overrides
    open override var intrinsicContentSize: CGSize {
        guard autoSizing, let font = font else { return super.intrinsicContentSize }
        
        let insets = textContainerInset.top + textContainerInset.bottom
        let numberOfLines = (contentSize.height - insets) / font.lineHeight
        let height = (numberOfLines.rounded(.up) * font.lineHeight) + insets
        
        return CGSize(width: UIView.noIntrinsicMetric, height: height)
    }
}