String hash

String.swift

extension String {
  // MARK: - Hashing

  func hash(to length: Int = 8) -> String {
    guard length > 0 else { return "" }

    let data = self.data(using: .utf8)!
    let hash = SHA256.hash(data: data)
    let hashData = Data(hash)

    let chars = Array("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789")

    let result = (0..<length)
      .map { i in
        let byte = hashData[i % hashData.count]
        let index = Int(byte) % chars.count
        return chars[index]
      }

    return String(result)
  }
}