[mattmanser]

While a lot of what you say is good, your opening assertion that his comment added nothing is nonsense.

He's right, you're right, js performance is still, in reality, pretty sucky in certain circumstances. It's worth talking about.

I remember writing an agonisingly slow program only 2 years ago and all that I was doing was a push/unshift, which at the time was for a mandelbrot generator I was making for fun, so had a loop of a few hundred thousand. A quick change of code and it was fine, but it was bizarre to be hitting something like that when every other language that I'd written the same code in hadn't even taken a second, let alone the minutes the javascript was taking.