alt Hacker News>you can produce very small binaries, for example with C
Not many people are going to want to be rolling their own libc like that author. Most people just compile their app and ship megabytes of webassembly at the expense of their users. To me webassembly is just a shortcut to ship faster because you don't have to port existing code.
> Not many people are going to want to be rolling their own libc like that author.
Emscripten provides a libc implementation based on musl, and so does wasi-libc (https://github.com/WebAssembly/wasi-libc).
If you explicitly list which functions you want to export from your WebAssembly module, the linker will remove all the unused code, in the same way that "tree-shaking" works for JS bundlers.
In my experience, a WebAssembly module (even with all symbols exported) is smaller than the equivalent native library. The bytecode is denser.
WebAssembly modules tend to be larger than JavaScript because AOT-compiled languages don't care as much about code size--they assume you only download the program/library once. In particular, LLVM (which I believe is the only mainstream WebAssembly-emitting backend) loves inlining everything.
Judicious use of `-Oz`, stripping debug info, and other standard code size techniques really help here. The app developer does have to care about code size, of course.