The Design of WebAssembly
I love the web. It is a modern-day superpower for the dissemination of information and empowerment of the individual. Of course, it has its downsides like trolling (largely possible through anonymity) and privacy issues, not to mention the problems of ownership and copyright infringement about to come into effect with the highly divisive article 13. But, let’s forget about that for just a moment and marvel at the technological innovation of the internet and the browsers which support it.
I first learnt to code in Javascript and have since been ridiculed by many for liking it. Yes, I know there are weird bits like this gem: [] == ![] // true but it has become one of the most ubiquitous languages on the planet thanks to the internet, browsers and the interpreters that run the code (Google’s V8 and Firefox’s SpiderMonkey to name a few).
As I got more into web development, I noticed a new name on the block: WebAssembly. As a computer science student and a developer, I believe one of the best ways to learn something is to try and understand why the engineers who built it made those design choices. So here is a brief look at some of the interesting design principles in WebAssembly and also why I think everyone should be excited.
Why do we need WebAssembly?
Okay, so first of all, to all my Javascript fans out there — no you shouldn’t be worried. When Javascript first came about, it was designed to be used in a lightweight way but has since gone on to do a lot of heavy lifting. Maybe it was used for manipulating some DOM elements, some client-side verification in forms but not everything that is trying to be done on the web now. Certainly not running fully-fledged games.
Why is Javascript not so fast or great? One of the main reasons is because it is an interpreted language. Scanning the code line by line and executing, luckily with Just-in-Time compilers, the efficiency improved massively but still there is only so much room to improve. But even then there’s the issue of Javascript’s dynamic typing causing another ceiling on performance
Alex Danilo discussed the improvements WebAssembly could make in his Google I/O talk in 2017. What really brought home the inefficiencies was his example add(a, b) function and the complexity that the Javascript interpreters have to go through in order to make sense of it.
