Javascript profanity match NOT replace

Question

I am building a very basic profanity filter that I only want to apply on some fields on my application (fullName, userDescription) on the serverside

Answer 1

The test method sets the lastIndex property of the regex to the current matched position, so that further invocations will match further occurrences (if there were any).

check.lastIndex // 0 (init)
filterString('ass'); // true
check.lastIndex // 3
filterString('ass'); // false
check.lastIndex // now 0 again

So, you will need to reset it manually in your filterString function if you don't recreate the RegExp each time:

function filterString(string) {
    check.lastIndex = 0;
    return check.test(string);
}

Btw, to match only full words (like "ass", but not "asster"), you should wrap your matches in word boundaries like WTK suggested, i.e.

var check = new Regexp("\\b(?:"+badWords.join('|')+")\\b", 'gi');

Answer 2

You are matching via a substring comparison. Your Regex needs to be modified to match for whole words instead

Answer 3

How about with fixed regexp:

check = new Regexp('(^|\b)'+badWords.join('|')+'($|\b)', 'gi');

check.test('ass') // true
check.test('suckass') // false
check.test('mass of whore') // true
check.test('massive') // false
check.test('slut is massive') // true

I'm using \b match here to match for word boundry (and start or end of whole string).