Trim trailing spaces before newlines in a single multi-line string in JavaScript

Question

Say I have this single string, here I denote spaces (\" \") with ^

^^quick^^^\\n
^brown^^^\\n
^^fox^^^^^\\n

What regular expression to use

Answer 1

Add the 'm' multi-line modifier.

replace(/\s+$/gm, "")

Or faster still...

replace(/\s\s*$/gm, "")

Why is this faster? See: Faster JavaScript Trim

Addendum: The above expression has the potentially unwanted effect of compressing adjacent newlines. If this is not the desired behavior then the following pattern is preferred:

replace(/[^\S\r\n]+$/gm, "")

Edited 2013-11-17: - Added alternative pattern which does not compress consecutive newlines. (Thanks to dalgard for pointing this deficiency out.)