A Regex to extract YouTube video ids from the given list of youtube URLs in Swift 4

ExtractYouTubeId.playground

//: Playground - noun: a place where people can play
//
//  Created by Pietro Basso on 29/06/2018.
//  Copyright (c) 2018 Pietro Basso. All rights reserved.
//

let urls = ["http://youtu.be/NLqAF9hrVbY",
            "http://www.youtube.com/watch?feature=player_embedded&v=DJjDrajmbIQ",
            "http://www.youtube.com/watch?v=dQw4w9WgXcQ",
            "http://www.youtube.com/embed/NLqAF9hrVbY",
            "https://www.youtube.com/embed/NLqAF9hrVbY",
            "http://www.youtube.com/watch?v=NLqAF9hrVbY",
            "http://www.youtube.com/v/dQw4w9WgXcQ",
            "http://youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US",
            "http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US",
            "http://youtube.com/watch?v=NLqAF9hrVbY",
            "http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo",
            "http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I",
            "http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/2/PPS-8DMrAn4",
            "http://gdata.youtube.com/feeds/api/videos/NLqAF9hrVbY",
            "http://www.youtube.com/watch?v=spDj54kf-vY&feature=g-vrec"]

/**
 Extract YouTube video id from url.
 
 Inspired from:
    - [NSRegularExpression - NSHipster](http://nshipster.com/nsregularexpression/)
    - [A stupid Regex to extract Youtube id from the given list of youtube URLs in Objective-C - zdk on GitHub](https://gist.github.com/zdk/4481771)
 */
func extractYouTubeId(from url: String) -> String? {
    let typePattern = "(?:(?:\\.be\\/|embed\\/|v\\/|\\?v=|\\&v=|\\/videos\\/)|(?:[\\w+]+#\\w\\/\\w(?:\\/[\\w]+)?\\/\\w\\/))([\\w-_]+)"
    let regex = try? NSRegularExpression(pattern: typePattern, options: .caseInsensitive)
    return regex
        .flatMap { $0.firstMatch(in: url, range: NSMakeRange(0, url.count)) }
        .flatMap { Range($0.range(at: 1), in: url) }
        .map { String(url[$0]) }
}

print(urls
    .map { extractYouTubeId(from: $0) }
    .compactMap { $0 }
)