Collisions when generating UUIDs in JavaScript?

Question

This relates to this question. I am using the code below from this answer to generate UUID in JavaScript:

\'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx\'.replace(/[         


        

Answer 1

I wanted to post this as a comment to your question, but apparently StackOverflow won't let me.

I just ran a rudimentary test of 100,000 iterations in Chrome using the UUID algorithm you posted and got no collisions. Here's a code snippet:

var createGUID = function() {
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
        return v.toString(16);
    });
}

var testGUIDs = function(upperlimit) {
    alert('Doing collision test on ' + upperlimit + ' GUID creations.');
    var i=0, guids=[];
    while (i++

Are you sure there isn't something else going on here?