Easy Javascript Regex Question

Question

Why doesn't this assign prepClass to the string selectorClass with underscores instead of non alpha chars? What do I need to change it to?

var regex = new RegExp("/W/", "g");
var prepClass = selectorClass.replace(regex, "_");

Answer 1

A couple of things:

• If you use the RegExp constructor, you don't need the slashes, you are maybe confusing it with the syntax of RegExp literals.
• You want match the \W character class.

The following will work:

var regex = new RegExp("\\W", "g");

The RegExp constructor accepts a string containing the pattern, note that you should double escape the slash, in order to get a single slash and a W ("\W") in the string.

Or you could simply use the literal notation:

var regex = /\W/g;

Recommended read:

• Regular Expressions (MDC)