import Foundation
import CryptoKit

extension String {

    /// trim 后空字符串返回 nil
    var rd_nilIfEmpty: String? {
        let trimmed = trimmingCharacters(in: .whitespacesAndNewlines)
        return trimmed.isEmpty ? nil : trimmed
    }

    /// SHA256 hex 摘要
    var rd_sha256Hex: String {
        let digest = SHA256.hash(data: Data(self.utf8))
        return digest.map { String(format: "%02x", $0) }.joined()
    }
}