InputValidator 1.0.3

InputValidator 1.0.3

LangLanguage SwiftSwift
License MIT
ReleasedLast Release Apr 2017
SwiftSwift Version 3.0
SPMSupports SPM

Maintained by Elvis Nuñez.



InputValidator is the easiest way to validate a value, things that InputValidator lets you validate:

  • Required (non-empty)
  • Maximum length
  • Minimum length
  • Maximum value
  • Minimum value
  • Valid characters
  • Format (regex)

For example if you want to validate that a value is between 5 and 6 you can do this:

let validation = Validation()
validation.minimumValue = 5
validation.maximumValue = 6

var result: Bool
let validator = InputValidator(validation: validation)
result = validator.validateString("4") // false
result = validator.validateString("5") // true
result = validator.validateString("6") // true
result = validator.validateString("7") // false

Find more information about the basic validations on the Validation repository.

It also helps you verify if a string should be inserted into another string, useful when validating inputs on a UITextField. For example validating the expiration date of a card, where the format is MM/YY, month is between 1-12 and YY is equal or later than the current year.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if (!string || [string isEqualToString:@"\n"]) return YES;

    CardExpirationDateInputValidator *inputValidator = [CardExpirationDateInputValidator new];
    return [inputValidator validateReplacementString:string withText:self.text withRange:range];

Included built-in input validators

  • CardExpirationDate
  • Decimal

Making your own input validator

InputValidator includes the InputValidatable protocol. Any class that conforms to this protocol can be considered an input validator. For example making an InputValidator that only allows letters could be as simple as this.

public struct LetterInputValidator: InputValidatable {
    public var validation: Validation?

    public init(validation: Validation? = nil) {
        self.validation = validation

    public func validateReplacementString(replacementString: String?, fullString: String?, inRange range: NSRange?) -> Bool {
        var valid = true
        if let validation = self.validation {
            let evaluatedString = self.composedString(replacementString, fullString: fullString, inRange: range)
            valid = validation.validateString(evaluatedString, complete: false)

        if valid {
            let composedString = self.composedString(replacementString, fullString: fullString, inRange: range)
            if composedString.characters.count > 0 {
                let letterCharacterSet = NSCharacterSet.letterCharacterSet()
                let stringCharacterSet = NSCharacterSet(charactersInString: composedString)
                valid = letterCharacterSet.isSupersetOfSet(stringCharacterSet)

        return valid

let validator = LetterInputValidator()
result = validator.validateString("A") // true
result = validator.validateString("2") // false
result = validator.validateString("AA") // true
result = validator.validateString("A7-w") // false


InputValidator is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'InputValidator'


InputValidator is available under the MIT license. See the LICENSE file for more info.


Elvis Nuñez, @3lvis