regex - What does the forward slash mean within a JavaScript regular expression?

Question

I can't find any definitive information on what / means in a JavaScript regex.

The code replace(/ /g, '');

What I'm able to figure out is this:

• / = I don't know
• = carriage return
• /g = I don't know but It may mean 'the match must occur at the point where the previous match ended.'

Answer 1

The slashes indicate the start and end of the regular expression.

The g at the end is a flag and indicates it is a global search.

From the docs:

Regular expressions have four optional flags that allow for global and case insensitive searching. To indicate a global search, use the g flag. To indicate a case-insensitive search, use the i flag. To indicate a multi-line search, use the m flag. To perform a "sticky" search, that matches starting at the current position in the target string, use the y flag. These flags can be used separately or together in any order, and are included as part of the regular expression.

To include a flag with the regular expression, use this syntax:

 var re = /pattern/flags;