Extension for Swift String

StringExtension

extension String {

    func range(of string: String) -> NSRange {
        return (self as NSString).range(of: string)
    }

    func initialLetter() -> String {
        guard let letter = first else { return "" }
        return String(letter)
    }

    static func empty() -> String {
        return ""
    }

    func isValidEmail() -> Bool {
        let regex = try! NSRegularExpression(pattern: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}", options: .caseInsensitive)
        return regex.firstMatch(in: self, options: [], range: NSRange(location: 0, length: count)) != nil
    }
}