Guid-validator-with-Regex

Guid-validator-with-Regex.txt

Example #1
------------
Use | in a regular expression to match either what comes before or what comes after:

const re = /^([0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12})|[0-9]+$/i;
console.log('11111111-1111-1111-8111-111111111111'.match(re)[0]);
console.log('5555'.match(re)[0]);

Example #2
------------
another way is to OR the matches in an if statement:

var reg1 = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
var reg2 = /^[0-9]*$/;
var text = " ... ";

if (reg1.test(text) || reg2.test(text)) {
  // do your stuff here
}
Another approach is ORing in the RegExp itself:

var regex = /(^[0-9]*)|^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
var text = " ... ";

if (regex.test(text)) {
  // do your stuff here
}



Example #3
------------
IsGuid() (Regular Expression Guid Match)
A regular expression for validating a string as being a Guid is..

@"^(\{{0,1}([0-9a-fA-F]){8}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){12}\}{0,1})$"

Example usage
Below is a function I try to keep handy which tests a string for a Guid and returns True or False.

public static bool IsGUID(string expression)
{
    if (expression != null)
    {
        Regex guidRegEx = new Regex(@"^(\{{0,1}([0-9a-fA-F]){8}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){12}\}{0,1})$");

        return guidRegEx.IsMatch(expression);
    }
    return false;
}