Sometimes wasmserve does not work with WSL (Windows Subsystem for Linux), other times it does (depends on the specific program being served with wasmserve).

This is a bug in WSL and not wasmserve. I am filing this issue here for visibility so that if others run into the same problem, they know what the cause is. To fix, you can either not use WSL (which works) or try an insiders version of WSL (I haven't so I cannot confirm if that fixes it).

The issue appears as follows:

Chrome will report that it fails to fetch the wasm binary due to a content length mismatch:

(index):4 GET http://localhost:8080/main.wasm net::ERR_CONTENT_LENGTH_MISMATCH 200 (OK)

One such case where this is known to occur is in https://github.com/gopherjs/vecty (just install wasmserve under Ubuntu WSL, cd example/markdown && wasmserve).

OS details: