Question

Can anybody please tell me why doesn’t this Regexp match?

var matches = ' @test'.match(new RegExp('(\s+|^)(@|!)(.*?)(\s+|$)', 'g'));

whereas this one matches:

var matches = '@test'.match(new RegExp('(\s+|^)(@|!)(.*?)(\s+|$)', 'g'));

I have already specified \s+. Why wouldn’t it match it then?

Answer 1

\s is not recognized as the whitespace shorthand because you’re constructing the regex from a string instead of a regex literal, and inside a string you need to double the backslashes.

So you need to use

var matches = ' @test'.match(new RegExp('(\\s+|^)([@!])(.*?)(\\s+|$)', 'g'));

or

var matches = ' @test'.match(/(\s+|^)([@!])(.*?)(\s+|$)/g);