WASM asset loading best practices

[3elDU]

When compiling the project for wasm, the filesystem is not available, since we're running in a browser. So how do you load assets? What are the best practices?
My first thought was to check if we are running in wasm, and in that case, load assets with http requests. For that we need to host those assets somewhere first, of course.
Maybe assets could be embedded in the wasm executable?
What are your thoughts?

[tinne26]

The most common approach is to use the https://pkg.go.dev/embed package in order to embed the assets directly into the compiled executable / wasm file. Most entries in the 2022 Ebitengine game jam did that. If you have many assets, though, yes, you would need to use http requests, but that's rarely necessary. Like, if you need to do that, you should be at a level where you can figure it out on your own.

[3elDU]

That worked fine! It's great I can even embed a whole directory.
The other issue I encountered though is using indexedDB from Go for saving/loading mechanic. Or speaking more generally, calling async JS functions from Go. I tried a lot of ways, and I either get a deadlock, or nothing happens at all.

[tinne26]

Honestly, using js from Go/wasm with syscall/js is a mess. It can be done, but it's not simple, e.g.: https://dev.to/clavinjune/golang-wasm-async-function-35j2. But this is really worth of a separate package, e.g. https://github.com/hack-pad/go-indexeddb.

[3elDU]

This looks like just what I wanted! Thanks, I'll take a look.