Is there a better way to clean a string?

Question

Currently, this is my code.

function clean_string(raw_string) {
    A =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 1234567890".split(
            ""
        );
    var cleaned_string = raw_string.toLowerCase();
    for (i = 0; i < cleaned_string.length; i++) {
        if (!A.includes(cleaned_string[i])) {
            cleaned_string = setCharAt(cleaned_string, i, " ");
        }
    }
    cleaned_string = cleaned_string.replace(/\s\s+/g, " ");

    return cleaned_string;
}

function setCharAt(str, index, chr) {
    if (index > str.length - 1) return str;
    return str.substring(0, index) + chr + str.substring(index + 1);
}

I don't know regex and it'll probably be easier with regex. Here's what I want to do:

Input: Hello, David World 123!

Output: hello david world 123

.

Input: hELlo., <>;dAVId world .;- 123

Output: hello david world 123

.

Input: He.llo David, w!orld 123#

Output: he llo david w orld 123

.

Basically what I want to do is replace anything but a-z0-9 with a space and then remove double spaces. In other words, I only want a-z0-9 in my results. How can I do that?

P.S. The code works but I think it looks bad and pretty inefficient.

EDIT: Sorry, I meant I only want lowercase letters in my output. I'm dumb.

Answer 1

A simple solution would be to convert all characters to lowercase, replace any character that isn't a-z, 0-9, or a space with a space character, and then replace multiple space characters with a single space character.

function sanitize(input) {
    return input
      .toLowerCase()
      .replace(/([^a-z\d\s]+)/g, ' ')
      .replace(/(\s+)/g, ' ');
}

console.log(sanitize('Hello, David World 123!'));
console.log(sanitize('hELlo.,     <>;dAVId  world  .;- 123'));
console.log(sanitize('He.llo     David,   w!orld 123#'));