Setup Emescripten toolchain.
https://emscripten.org/docs/getting_started/downloads.html
Then build TinyUSDZ with emcmake
$ cd <tinyusdz>/sandbox/emscripten
$ emcmake cmake -DCMAKE_BUILD_TYPE=Release -B build_em -S ../../
This just build a library. No example yet.
You can also look into <tinyusdz>/examples/sdlviewer. sdlviewer example has an option to built it with Emscripten.
EoL.