Here is what I'm trying to do.

Right now I can parse a number by adding commas automatically, however, when I try to type a negative it goes away.

Here is the current code that I'm using to parse the number:

      $(this).val(function(index, value) {
          return value
                .replace(/\D/g, "")
                .replace(/\B(?=(\d{3}) (?!\d))/g, ",");
            }); 

How do I keep the number negative value?

CodePudding user response：

\D matches anything that isn't a decimal digit, so you're removing the minus sign. Use [^-\d] instead to remove anything that isn't a digit or minus sign.

function add_commas(value) {
  return value
    .replace(/[^-\d]/g, "")
    .replace(/\B(?=(\d{3}) (?!\d))/g, ",");
}

console.log(add_commas('1234567'));
console.log(add_commas('-1234567'));
console.log(add_commas('-123,4X567'));

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

Caveat: this won't work correctly if they put a - in the middle of the number, since it will be left in the number.