Question

I am lost about how this works:

x=x.replace(/^\s+|\s+$/g,"");

What is the pipe( | ) for ?

Answer 1

It means or. The part to the left matches any leading spaces (^), the part to the right matches any trailing space ($). The g modifier allows this matching to be applied more than once, which is useful if you’re expecting both trailing and leading space.

Basically this regex trims whitespace.

An alternative way to write this regex is, using the new RegExp construct:

x = x.replace(new RegExp("^\s+|\s+$", "g"), "");

If find this notation more readable because you don’t need your delimiters (/) and your modifier is separated.