javascript parseInt when value = 0

Question

I'm using jquery.grep to clean a string and return only digits.

This is what I have:

var TheInputArray = TheInput.slice();
var TheCleanInput = jQuery.grep(TheInputArray, function (a) {
  return parseInt(a, 10);
});

I take a string, split it into an array and use the parseInt function to check if it's a number. The problem is that when the value of a is 0, it skips that element. What changes do I need to do to make this code work?

Thanks.

Answer 1

Unfortunately, 0 in Javascript is falsy. So you need to be sure your return value is true, even for a 0.

var TheInputArray = TheInput.slice();
var TheCleanInput = jQuery.grep(TheInputArray, function (a) {
  return ! isNaN(parseInt(a, 10));
});

parseInt returns NaN (not a number), if it fails to parse the input. And isNan() will return true if the argument is NaN. So this should help you detect that case.

Answer 2

You can use regular expressions:

var TheCleanInput = TheInput.replace(/\D/g, '');