The instructions for building a Hello World example list the files that will be generated in pkg, along with descriptions of them. Two files (wasm_game_of_life_bg.js and wasm_game_of_life_bg.wasm.d.ts) are generated, but are not in that list.

I am new to wasm-pack, but I think these generations may have been added relatively recently, after this documentation was written. I've found bugs that discuss adding those files to the generated package.json (drager/wasm-pack#1193 and drager/wasm-pack#199).