"javascript 正则表达式（用户名验证）"

Question

I want to enforce that

Answer 1

The code you have looks fine, aside from the inconsistent variable reference (see the comment by Josh Purvis ).

The following regex is fine for your first name spec:

var nameRegex = /^[a-zA-Z\-]+$/;

Adding digits for your username check is straightforward:

var usernameRegex = /^[a-zA-Z0-9]+$/;

Note: There are many ways to write regular expressions. I've chosen to provide a version that matches what you started with. I encourage you to work through this Regular Expression Tutorial

Answer 2

Here's the validation function I came up with, tailor it for your own use-cases:

function isUserNameValid(username) {
  /* 
    Usernames can only have: 
    - Lowercase Letters (a-z) 
    - Numbers (0-9)
    - Dots (.)
    - Underscores (_)
  */
  const res = /^[a-z0-9_\.]+$/.exec(username);
  const valid = !!res;
  return valid;
}

Answer 3

Usernames can only use letters, numbers, underscores, and periods.

  const onValidUsername = (val) => {
    const usernameRegex = /^[a-z0-9_.]+$/
    return usernameRegex.test(val)
  }