Variable in match (javascript)

Question

<body class="reviews"></body>

var body = document.body;
var target = 'reviews';

if (body.className.match('/\b' + target + '\b/'))
    console.log(true);
else
    console.log(false);

This code returns false. But if I use body.className.match(/\breviews\b/) it returns true.

What's wrong with it?

I tried to escape a variable in a regex, no luck.

possible duplicate of Regular Expression Pattern With A Variable — I Hate Lazy
– I Hate Lazy, Commented Dec 4, 2012 at 21:13

gen_Eric · Accepted Answer · 2012-12-04 21:13:44Z

3

You are searching for the literal string '/\breviews\b/', it's not being read as a RegEx.

You need to use the new RegExp method.

body.className.match(new RegExp('\\b' + target + '\\b'))

Note: Don't use delimiters with new RegExp. Also, note that \\b has 2 \.

answered Dec 4, 2012 at 21:13

gen_Eric

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2 Comments

Michael Berkowski Over a year ago

Double-escape the \\b inside the quoted string?

gen_Eric Over a year ago

@MichaelBerkowski: Thanks, forgot about that :-)

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