String+base64.swift

extension String {
    func base64Encoded() -> Data? {
        return self.data(using: .utf8)
    }

    func base64Decoded() -> Data? {
        if self.range(of: ":")?.lowerBound != nil {
            return self.data(using: .utf8)
        }
        let base64String = self.replacingOccurrences(of: "-", with: "+").replacingOccurrences(of: "_", with: "/")
        let padding = base64String.count + (base64String.count % 4 != 0 ? (4 - base64String.count % 4) : 0)
        return Data(base64Encoded: base64String.padding(toLength: padding, withPad: "=", startingAt: 0), options: NSData.Base64DecodingOptions(rawValue: 0))
    }
}