Recently, JavaScript compilers seem to be appearing almost as quickly as new frameworks.

Let’s ask a simple question: why? Why are there so many of them? What are the differences between them? Do we have to fire up the entire V8 every time we want to run a few lines of JavaScript? Is V8 a compiler, interpreter or optimiser? Finally: is JavaScript a slow language and why does Chrome eat up so much memory?

Answering this questions will help you understand how your JavaScript code is run, do you have to worry about the performance of the language and how can you optimise for cases where you really have to worry.