Tree Shaking the Bytes Away

Today, JavaScript has become incredibly powerful. But with great power comes great responsibility - and every feature you add to your application or library results in additional bytes that have to be delivered to your users over the network. One way to deal with this is “tree shaking” - a technique to remove unused code from your application. While most modern bundlers like Webpack and Vite will automatically do this for you, their ability to do so properly depends a lot on how you write your code. This talk will explain the concept of tree shaking in general, and explore typical scenarios where code becomes un-tree-shakeable, as well as how these can be improved. I will show some concrete examples of the benefits of tree shaking, and of code I refactored to reduce the bundle size of applications drastically. I will also show how you can measure & test how tree shakeable your code is.