Apply maximum and minimum limit in Regex

Question

Here is my username regex, i want to apply limit that allow only 3 characters minimum and 15 characters maximum.

 /^[A-Za-z0-9]+(?:[_-][A-Za-z0-9]+)*$/

This Regex Validate below criteria

• Usernames can consist of lowercase and capitals
• Usernames can consist of alphanumeric characters
• Usernames can consist of underscore and hyphens
• Cannot be two underscores, two hypens or two spaces in a row
• Cannot have a underscore, hypen or space at the start or end

Answer 1

^(?=.{3,15}$)[A-Za-z0-9]+(?:[_-][A-Za-z0-9]+)*$

Just add a lookahead.See demo.

https://regex101.com/r/uE6jQ1/12