【Swift】DateFormatterが効かない

Question

date型を日本時間のdate型に変えたいのでstringにしてから再度date型に戻したのですが、
文字列からdate型がうまくいきません

var date = Date(timeIntervalSince1970: messageData["createTime"] as! TimeInterval)
                let dateStr = date.toStringWithCurrentLocale()
                print(dateStr)
                let formatter = DateFormatter()
                formatter.locale = Locale(identifier: "ja_JP")
                formatter.dateFormat = "yyyy-MM-dd HH:mm"
                date = formatter.date(from: dateStr)!
                print(date)

Answer 1

これでうまくいった
dateからstring
stringからdate

var date = Date(timeIntervalSince1970: messageData["createTime"] as! TimeInterval)
                let dateStr = date.toStringWithCurrentLocale()
                print(dateStr)
                date = DateFormatter.current("yyyy-MM-dd HH:mm").date(from: dateStr)!
                print(date)

extension Date {
    
    func toStringWithCurrentLocale() -> String {
        
        let formatter = DateFormatter()
        formatter.timeZone = TimeZone.current
        formatter.locale = Locale.current
        formatter.dateFormat = "yyyy-MM-dd HH:mm"
        
        return formatter.string(from: self)
    }
    
}

extension TimeZone {
    static let gmt = TimeZone(secondsFromGMT: 0)!
    static let jst = TimeZone(identifier: "Asia/Tokyo")!
}

extension Locale {
    static let japan = Locale(identifier: "ja_JP")
}

extension DateFormatter {
    static func current(_ dateFormat: String) -> DateFormatter {
        let df = DateFormatter()
        df.timeZone = TimeZone.gmt
        df.locale = Locale.japan
        df.dateFormat = dateFormat
        return df
    }
}

extension Date {
    static var current: Date = Date(timeIntervalSinceNow: TimeInterval(TimeZone.jst.secondsFromGMT()))
}