new Regexp doesn't work [duplicate]

Question

I'm trying to convert following expression to "new Regexp()" style:

http://jsfiddle.net/HDWBZ/

var Wyrazenie = /\btest[a-z]*/g;

I'm really confused with it and have no idea how to fix it. Below is what I've done but obviously it doesn't work.

var Wyraznie = new RegExp("\btest[a-z]*","g");

Also have a question how would it look if instead of "test" I would use variable?

Answer 1

You should use this instead...

new RegExp("\\btest[a-z]*", "g");

... as \b will be interpolated into a single (slashless) character when JavaScript parser works through the corresponding string literal. The solution is to escape slash itself.

DEMO: http://jsfiddle.net/HDWBZ/1/