Question

In the pursuit of understanding JavaScript/OOP better, I’m curious how regular expression argument parameters are handled in JavaScript. I already understand a lot about regular expressions, so this isn’t about interpreting patterns. This is about identifying how JavaScript handles it.

Example:

newStr = str.replace(/(^\W*|\W*$)/gi,'');

This basically trims any special characters and white-space from a string. However, /(^\W*|\W*$)/gi is not an encapsulated string, therefore, it baffles me to understand this concept since the JS object is not a string, nor a number. Is this object-type alone (i.e., regex-only), or does it serve other purposes?

Answer 1

It’s just a special syntax that JavaScript has for regular expressions. It evaluates to an object, and is no different than:

var rex = /(^\W*|\W*$)/gi;
decision = str.replace(rex, '');

Or:

var rex = new RegExp('^\\W*|\\W*$', 'gi');

The RegExp MDN documentation has plenty of detailed info.