Javascript Regex - sanitize string with whitelist

Question

I have a very basic RegEx problem. I'm trying to sanitize an input field with a whitelist. I'm trying to only allow numbers and a decimal into my field. If a user types an invalid character, I want to strip it out of the input and replace the input with a clean string.

I can get it working with only numbers, but I can't get the decimal into the allowed pool of characters:

var sanitize = function(inputValue) {
    var clean = "",
        numbersOnly = /[^0-9]/g;  // only numbers & a decimal place
    if (inputValue) {
        if (numbersOnly.test(inputValue)) { 
            // if test passes, there are bad characters
            for (var i = 0; i < inputValue.length; i++) {
                clean += (!numbersOnly.test(inputValue.charAt(i))) ? inputValue.charAt(i) : "";
            }
            if (clean != inputValue) {
                makeInputBe(clean);
            }
        }
    }
};

Working fiddle

in ES6 I believe you can use Number.isFloat(inputValue) || Number.isInteger(inputValue) — Sterling Archer
– Sterling Archer, Commented Jul 31, 2014 at 17:06
I'm not. My fiddle only works with numbers, but I can't get the decimal in there. I can't figure out the RegEx string to allow it. — Scott
– Scott, Commented Jul 31, 2014 at 17:08

anubhava · Accepted Answer · 2014-07-31 17:06:01Z

6

Rather than looping your input character by character and validating each character you can do this for basic sanitizing operation:

var s = '123abc.48@#'
s = s.replace(/[^\d.]+/g, '');
//=> 123.48

PS: This will not check if there are more than 1 decimal points in the input (not sure if that is the requirement.

answered Jul 31, 2014 at 17:06

anubhava

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