Javascript RegExp non-capturing groups

It matches #foo and #bar because the outer group (#1) is capturing. The inner group (#2) is not, but that' probably not what you are checking.

If you were not using global matching mode, an immediate fix would be to use (/(?:#)([a-zA-Z0-9\-_]*)/ instead.

With global matching mode the result cannot be had in just one line because match behaves differently. Using regular expression only (i.e. no string operations) you would need to do it this way:

var re = /(?:#)([a-zA-Z0-9\-_]*)/g;
var matches = [], match;
while (match = re.exec("#foo#bar")) {
    matches.push(match[1]);
}

See it in action.

I'm not sure if you can do that using match(), but you can do it by using the RegExp's exec() method:

var pattern = new RegExp('#([a-zA-Z0-9\-_]+)', 'g');
var matches, ids = [];

while (matches = pattern.exec('#foo#bar')) {
    ids.push( matches[1] ); // -> 'foo' and then 'bar'
}

You could use .replace() or .exec() in a loop to build an Array.

With .replace():

var arr = [];
"#foo#bar".replace(/#([a-zA-Z0-9\-_]*)/g, function(s, g1) {
                                               arr.push(g1);
                                          });

---

With .exec():

var arr = [],
    s = "#foo#bar",
    re = /#([a-zA-Z0-9\-_]*)/g,
    item;

while (item = re.exec(s))
    arr.push(item[1]);