Swift 4: Convert Unix Timestamp to a nicely formatted Date & Time

I needed to convert a Unix Timestamp, which for some inexplicit reason was being returned as a String by an API I was using and this is the super foolish function I ended up with. I am not going to shame the API Provider for returning a timestamp as a String 😉

func createDateTime(timestamp: String) -> String {
    var strDate = "undefined"
        
    if let unixTime = Double(timestamp) {
        let date = Date(timeIntervalSince1970: unixTime)
        let dateFormatter = DateFormatter()
        let timezone = TimeZone.current.abbreviation() ?? "CET"  // get current TimeZone abbreviation or set to CET
        dateFormatter.timeZone = TimeZone(abbreviation: timezone) //Set timezone that you want
        dateFormatter.locale = NSLocale.current
        dateFormatter.dateFormat = "dd.MM.yyyy HH:mm" //Specify your format that you want
        strDate = dateFormatter.string(from: date)
    }
        
    return strDate
}