How to sanitize using javascript regex - case insensitivity + whitespaces + whole word

Question

Suppose I have string variable:

var animals = "catdog caT dog cat";

I don't want cats, big caTs, and messy whitespaces. I've tried to use:

var rep = "cat"
var nocats = animals.replace(new RegExp(rep, 'g'), '');

and nocats is now "dog caT dog ", while I need "catdog dog"

What regexp should I use ?

Esailija · Answer 1 · 2012-08-22T15:18:07.540

2

Use \b for word boundary and case insensitive (i flag) regex:

var animals = "catdog caT dog cat",
    animal = "cat"


animals.replace(new RegExp("\\b" + animal + "\\b", "gi"), "");
// "catdog  dog " needs additional trimming

edited Aug 22 '12 at 15:18

answered Aug 22 '12 at 15:04

Esailija

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`.trim()` or `.replace(/\s*$/,"").replace(/^\s*/,"")` should be included. – Christoph Aug 22 '12 at 15:14
Thanks, but I also need "cat" to be a variable so I suppose I should use RegExp, should I ? – jwaliszko Aug 22 '12 at 15:16
@JarekWaliszko I have now done so, you should also escape it for regexp if it's user input – Esailija Aug 22 '12 at 15:18
@Esailija: perhaps replace trailing spaces, too? `"catdog caT dog cat dog".replace(new RegExp('\\b'+animal+'\\b\\s?','gi'),'')` – Elias Van Ootegem Aug 22 '12 at 15:56

score 0 · Accepted Answer · edited May 23 '17 at 11:56

I note that your question is not entirely clear on how exactly you would like whitespaces in the string to be treated. Assuming you want to collapse the whitespace in the source string, this should work:

// " catdog      caT  dog    cat" --> "catdog dog" 
animals.replace(new RegExp('\\s*\\b' + animal + '\\b\\s*|\\s+', 'gi'), ' ').trim();

Also make sure you are aware of the semantics of the word boundary assertion - "cat-dog" will be replaced to "-dog" in this case. An alternative will be

// " cat_dog cat-dog cat dog catdog catcatdog " --> "cat_dog cat-dog dog catcatdog" 
animals.replace(new RegExp('(^|\\s+)' + animal + '(\\s+|$)|\\s+', 'gi'), ' ').trim();

For reference: What is a word boundary in regexes?

Thanks for the tip about word boundary – jwaliszko Aug 24 '12 at 13:48 — jwaliszko, Aug 24 '12 at 13:48

How to sanitize using javascript regex - case insensitivity + whitespaces + whole word

2 Answers2