extension String {

    func htmlEscaped() -> String {
        replacingOccurrences(of: "&", with: "&")
            .replacingOccurrences(of: "\"", with: """)
            .replacingOccurrences(of: "'", with: "'")
            .replacingOccurrences(of: "<", with: "&lt;")
            .replacingOccurrences(of: ">", with: "&gt;")
    }

    var nonEmpty: String? {
        isEmpty ? nil : self
    }
}

extension String {

    var fileExtension: String? {
        let parts = components(separatedBy: ".")
        guard parts.count > 1 else { return nil }
        return parts.last
    }

    var fileNameAndExtension: (fileName: String, fileExtension: String?) {
        let parts = components(separatedBy: ".")
        guard parts.count > 1 else {
            return (self, nil)
        }
        return (fileName: parts.dropLast().joined(separator: "."), fileExtension: parts.last)
    }
}