[brabel]

To really understand WASM, you should try to write it by hand! That's right, it's possible, it even has a text format that all WASM runtimes let you run directly.

Check this out: https://blog.scottlogic.com/2018/04/26/webassembly-by-hand.h...

Once you know what WASM really does, it's obvious why you need JS (or whatever the host language is in your runtime, which could be anything) to provide anything related to IO and why there's zero chance you'll get DOM access as it currently stands... until they finally finish off specifying a whole lot of APIs (they did GC already which was pretty fundamental for that to work, but there's many more things needed for complete access to IO and DOM).

If you use a compiler like Rust, it's going to include WASI which is a sort of POSIX for WASM (and currently completely underdefined, just try to find the spec and you'll see it's mostly being made up as implementers go), which is why you'll get ridiculous amounts of code into your WASM file. If you write it by hand, importing some made up function like `console_log` which you then import from WASM, then your WASM should be just a few bytes! Literally. I wrote a little compiler to do this as it's not hard to generate WASM bytecode, but to make anything useful is very painful due to the complete lack of specifications of how things should work (e.g. to print a string is actually very hard as you'll just be able to give JS or your host a pointer to linear memory, and then you need to write the actual bytes - not UTF or even ASCII characters in WASM itself - to linear memory, which the JS then has to decipher to be able to call its own `console.log()`)... so I am waiting (a few years by now) until this improves to continue.