The five stages of JavaScript performance grief

A presentation at JS Monthly in in London, UK by Simon Hearne

We use JavaScript for everything, but how well do we understand how it performs? There are benchmarks out there for different frameworks, JS engines and libraries that give us an idea. But it becomes much harder to measure performance once we start writing our own code, extending libraries and delivering code to real people.

We often forget that real people have to use our apps. It’s also easy to forget that we are not real people, and that performance benchmarks aren’t run by real people and that real people don’t all have £800 smartphones to run our apps on.

Let’s have a look at the effect that JS has on user experiences, why it is such a critical issue, and some quick wins to improve the experience for those weird real people.