U.S. Zip Code Validation in Swift

Here is a small function that will validate a US Zip Code using a Regexp with a: NSPredicate in Swift.

func validate(input: String?) -> Bool {
    guard let input = input else { return false }

    return NSPredicate(format: "SELF MATCHES %@", "^\\d{5}(?:[-\\s]?\\d{4})?$")
        .evaluate(with: input.uppercased())
}

Playground: zip-code-validation-playground