In her wasm summit presentation [1], Ashley Williams had a slide that showed a different picture. AssemblyScript came out with the smallest footprint, while Rust and C (through Emscripten) had bigger footprints--the slide is qualitative.

An article posted last week on HN [2] also seems to support this hypothesis, this time with some numbers. The AssemblyScript program had 6% the filesize of the Rust program.

So it seems like, if you want small wasm libraries, AssemblyScript may be your best shot.

  [1] https://youtu.be/J5Rs9oG3FdI?t=2133
  [2] https://news.ycombinator.com/item?id=33761756