[Codewars] Simple validation of a username with regex (8 kyu) / JavaScript

https://www.codewars.com/kata/56a3f08aa9a6cc9b75000023

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DESCRIPTION:

Write a simple regex to validate a username. Allowed characters are:

• lowercase letters,
• numbers,
• underscore

Length should be between 4 and 16 characters (both included).

 

코드

function validateUsr(username) {
  res = /^[0-9a-z_]{4,16}$/.test(username)
  return res
}