Question

I came across this JavaScript function and I don’t understand quite what it’s doing, especially with the use of 0xF.

What does the 0xF do, exactly. It looks like a null nibble to me.

function()
{
    var g = "";
    for(var i = 0; i < 32; i++)
        g += Math.floor(Math.random() * 0xF).toString(0xF)
    return g;
}

Answer 1

0xF == 15. It’s simply hexadecimal notation.

However, that snippet is not actually creating a GUID, it’s just stringing a bunch of random integers together. It’s not possible to create a GUID in JavaScript, because generating one requires parameters that the VM can’t access (network address, etc).

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See also my answer to this question: How to create a GUID in Javascript?