Why is Vite fast

Because it uses native ESM instead of bundling

• When a file is edited in a bundler-based build setup, it is inefficient to rebuild the whole bundle for obvious reasons: the update speed will degrade linearly with the size of the app
• This is why some bundlers support Hot Module Replacement (HMR): allowing a module to “hot replace” itself without affecting the rest of the page. This greatly improves DX - however, in practice we’ve found that even HMR update speed deteriorates significantly as the size of the application grows
• In Vite, HMR is performed over native ESM. When a file is edited, Vite only needs to precisely invalidate the chain between the edited module and its closest HMR boundary (most of the time only the module itself), making HMR updates consistently fast regardless of the size of your application