Check out example codes for "url encode xcode". It will help you in understanding the concepts better.

Code Example 1

extension String {
    private static let slugSafeCharacters = CharacterSet(charactersIn: "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-")

    public func convertedToSlug() -> String? {
        if let latin = self.applyingTransform(StringTransform("Any-Latin; Latin-ASCII; Lower;"), reverse: false) {
            let urlComponents = latin.components(separatedBy: String.slugSafeCharacters.inverted)
            let result = urlComponents.filter { $0 != "" }.joined(separator: "-")

            if result.count > 0 {
                return result
            }
        }

        return nil
    }
}

Code Example 2

func addingPercentEncoding(withAllowedCharacters allowedCharacters: CharacterSet) -> String?

Learn ReactJs, React Native from akashmittal.com