What is the best way to detect retina support on a device using JavaScript?

Question

Right now I am using this function:

function is_retina_device() {
    return window.devicePixelRatio > 1;
}

But its simplicity scares me

Answer 1

devicePixelRatio is not reliable at all. when you zoom in to 200%, the window.devicePixelRatio will return you 2, but you are not on a retina display.