XIBDesignable

XIBDesignable.swift

//
//  XIBDesignable.swift
//
//  Created by Michael Kral on 8/15/17.
//
import UIKit

protocol XIBDesignable {
    func xibSetup()
}

extension XIBDesignable where Self: UIView {
    func xibSetup(){
        let view = loadViewFromNib()
        view.frame = bounds
        view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        addSubview(view)
    }
    
    private func loadViewFromNib() -> UIView {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: String(describing: Self.self), bundle: bundle)
        let view = nib.instantiate(withOwner: self, options: nil).first as! UIView
        return view
    }
}

You can really make loadViewFromNib a private func as it's not expected to be called outside of xibSetup, but other than that a great gist!

@gligorkot, just fixed it. Thanks!