REGEX VALIDATOR HOW TO
REGEX VALIDATOR CODE

If you need extra regexes, just add a case to your enum. Not only, now all the patterns for our regular expressions are in one single place of our code.

REGEX VALIDATOR CODE

Let’s see now how readable our code is now: let isValid = “Username”.isValidWith(regexType. Writing clean code is our main goal often. Please remember to add small comments to every case of the enum in order to clarify everything.

Line 40: our previous function with a small modification (see line 43).

Wrapping it in a enum makes everything ultra readable.

Line 14: here I’ve created a private var pattern: String that returns the regex code.

With this little variable, we are ready for everything. It’s common to have different string limits for a textual input in an app.

Lines 8–9: I’ve used an associated value in my enums in order to give more flexibility to the rule.

Line 5: I’ve created a none rule… just in case, you never know.

Take a look at this article for this technique. It is very common part of the web-application to include email address, and for this we require to validate if email address is correct and acceptable to save in database or not, so in this post, I have explained how we can validate email address in C using regex and without using regex also (using data annotation in mvc).

Line 4: I’ve created a nested type inside Foundation String. When the Declarative plugin is used, the regexp validator will be turned on automatically if the input uses HTML 5 pattern attribute.

Let’s build a whole manager inside the String Extension:Īs you can see I’ve created some examples to show you this approach. Luckily Swift gives us a pretty clean solution… we can use enum cases! If the answer is yes… well, you do not need this article and I’m sorry to say that you have wasted three minutes of your life 😁 … do not read anymore 😉. The second issue is readability… can you tell me what is this regex for? let isValid = “Username”.isValidWith(regex: #”^(?:||(?:|))$”#) What if you validate a user name in seven points of your app and the Business Department decides to change the validation rule? Maybe allowing blank spaces now? I assure you that you will not change the regex in all seven places and you will and up with a bug… maybe spotted a month later in production. If you write the regex pattern every time you need it you will eventually have problems and a so-called technical debt. If you are working on a big project, you will need to perform the same validation over and over in different sections. This solution is pretty nice but I see two issues here. Allows validate if the value of a field matches a regular expression use PhalconValidationValidatorRegex as RegexValidator validator->add( createdat. It could be enough but we still have room for improvements. A regular expression (shortened as regex or regexp also referred to as. Wow! Much clearer and much more readable! Create a reusable Regex Text Validator Manager in Swift for your projects. Let’s take a look at our calling function now: let isValid = “UserName”.isValidWith(regex: #”^+$”#)

Validate the text with the regex finding if there is an firstMatch in it.Ī first simplistic solution would be to create a function for the test: A validator that validates whether the input matches the provided regular expression.

Create an NSRange with the string text, you want to validate… you could even validate just a section of your input text, hence the range.

Create an NSRegularExpression object with the regex pattern you want to apply.

The Foundation the framework comes with a bunch of methods to deal with regexes, so validating a text is really easy.

REGEX VALIDATOR HOW TO

If you want to learn how to create a regex, take a look at one of my latest articles where I showed you a really handy online tool. It is a technique developed in theoretical computer scienceand formal language theory.īasically, it’s a string with its own rules given to functions apt to analyze an input text and check if it matches the rules stated in the regex itself. Usually such patterns are used by string-searching algorithms for “find” or “find and replace” operations on strings, or for input validation.

Var phoneNumber = document.getElementById( 'phone-number').Let’s start with some definitions taken from Wikipedia:Ī regular expression (shortened as regex or regexp also referred to as rational expression) is a sequence of characters that specifies a search pattern in text.

Regex validator