React.lazy() Route Code Splitting Explained

Related: JavaScript Bundle Analysis: Tree Shaking and Code Splitting Explained covers how bundlers construct module graphs and where tree shaking fails, which is the foundation for understanding what code splitting actually does. The size of your JavaScript bundle is not the number that matters for first load. What matters is how much of that bundle is needed to render the page the user actually landed on. A 5MB React application where the user landed on the marketing homepage might need 80KB to