It does take a lot of space for devs, but personally I find that absolutely irrelevant, because it's your end user's experience that really matters, and - as a dev - you are most likely to have a much better rig and internet connection than your average Joe.

Tree shaking is essentially reducing the amount of included code to only the stuff being used.

Let’s say you have a JAR, DLL, or whatever with 5 functions.

Your application calls function A which also calls function B of the DLL/jar.

Tree shaking says “hmm, if I follow the code execution path, I only need 2/5 functions from the DLL/jar” and discards the remaining 3/5 functions.

This significantly reduces the bundle size (the bundle is what is sent to the browser).

Some use 'pnpm' package manager, alternative to default, where the packages are downloaded once to a central location, and per project directory, it links to the original location so files aren't duplicated saving space