I thought that as well, if you are going to use setImmediate, it would probably make the most sense to just a web worker which is actually standardized and supp

I thought that as well, if you are going to use setImmediate, it would probably make the most sense to just a web worker which is actually standardized and supported in all browsers (and won't turn your quick sort fn into a mess). However it looked like he needed to support IE8, so this might be an ok solution (although I would argue a terrible one for anyone who doesn't need to support IE8/9).