Extract data between characters using regex?

Question

I have a string something like [[user.system.first_name]][[user.custom.luid]] blah blah

I want to match user.system.first_name and user.custom.luid

I built /\[\[(\S+)\]\]/ but it is matching user.system.first_name]][[user.custom.luid.

Any idea where I am doing wrong?

Answer 1

Make it non-greedy as

/\[\[(\S+?)\]\]/

Regex Demo

Answer 2

Make it non-greedy using ? to match as few input characters as possible. That your regex will be /\[\[(\S+?)\]\]/

var str = '[[user.system.first_name]][[user.custom.luid]] blah blah'
var reg = /\[\[(\S+?)\]\]/g,
  match, res = [];

while (match = reg.exec(str))
  res.push(match[1]);

document.write('<pre>' + JSON.stringify(res, null, 3) + '</pre>');

Answer 3

If you need 2 separate matches use:

\[\[([^\]]*)\]\]

Regex101 Demo

Answer 4

I think /[^[]+?(?=]])/g is one fast regex. Turns out to be completed in 44 steps

[^[]+?(?=]])

Debuggex Demo

Regex101

var s = "[[user.system.first_name]][[user.custom.luid]]",
    m = s.match(/[^[]+?(?=]])/g);
document.write("<pre>" + JSON.stringify(m,null,2) + "</pre>") ;