Open the twitter app from your own app using Swift

openTwitterFunc.swift

    func openOnTwitter() {
        let screenName =  "jack"
        let appURL = URL(string: "twitter://user?screen_name=\(screenName)")!
        let webURL = URL(string: "https://twitter.com/\(screenName)")!
        
        let application = UIApplication.shared
        
        if application.canOpenURL(appURL) {
            application.open(appURL, options:  [:], completionHandler:  nil)
        } else {
            application.open(webURL, options:  [:], completionHandler:  nil)
        }
    }