JS: how to remove "spammy invisible chars"?

Question

Some user is flooding with some chars that bypass regex filters. when I paste that chars into UTF8 editor, they look same (except the flood version is not selectable completly: it seems to be some invisible chars inserted

And when you switch to ANSI encodage, you clearly see the difference of the 2 words liebehomo lâ€iâ€ebâ€ehâ€oâ€mo

When I paste that spammy word into developer tool, I get

s.length gives 14 and not 9 !

So my question is: how would it be possible to filter these spammy words that contains some strange chars ?

It's been a while since I messed with this but have you tried splitting the string? And then testing each char through a loop? — EasyBB, Jul 30 '20 at 22:46
In case anyone who runs into the same issue sees this, the following seems to work: `str.replace(/\p{C}/gu, '');`. Note that the `u` flag is required for this to work. I'm not sure if this works for all invisible characters, though (kinda hard to test) — paddotk, Mar 28 '22 at 15:23

score 0 · Answer 1 · answered Jul 30 '20 at 22:45

0

Probably as simple as replacing any non-printable character first:

string = string.replace(/[^ -~]+/g, "");

document.getElementById('demo').addEventListener('input', function(e) {
    e.target.innerHTML = e.target.innerHTML.replace(/[^ -~]+/g, "");
    console.log(e.target.innerHTML);
});

<textarea id="demo"></textarea>

answered Jul 30 '20 at 22:45

dave

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That's not checking for printable characters, but rather for ASCII characters only. – Bergi Jul 31 '20 at 00:49
Could you explain that regex please ? – yarek Jul 31 '20 at 13:32

JS: how to remove "spammy invisible chars"?

1 Answers1