Swift custom date decoder. ISO8601 without milliseconds

iso8601.swift

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .custom { decoder -> Date in
    let valueContainer = try decoder.singleValueContainer()
    let value = try valueContainer.decode(String.self)

    if let regex = try? NSRegularExpression(pattern: "\\.\\d+", options: []) {
        let result = regex.stringByReplacingMatches(in: value, options: [], range: NSRange(location: 0, length: value.count), withTemplate: "")

        if let date = ISO8601DateFormatter().date(from: result) {
            return date
        }
    }

    let context = DecodingError.Context(codingPath: valueContainer.codingPath, debugDescription: "Invalid date")
    throw DecodingError.dataCorrupted(context)
}

// decodes 1970-01-01T00:00:00.111Z as 1970-01-01T00:00:00Z