WASM with Go

Objective

Build an implementation of the sandpiles algorithm with a graphical display using Go as the data processing layer and the browser as the presentation layer

Open Questions

What is the fastest way to send data between Go and JS? Is Go fast at updating the DOM? How hard is it to build/deploy a Go-wasm app?

1st step: config

A bit tricky and magical. The wasm_exec.js file is the magical glue that makes the .wasm output interface with the browser. M A G I C A L G L U E Not too hard, make sure GOOS = js and GOARCH = wasm

2nd step: Write in Go

Go is fun, Go is fast.

func initSandpilesWrapper() js.Func {
	initFunc := js.FuncOf(
		func(this js.Value, args []js.Value) interface{} {
            // Stuff that happens
            // return interface{}
        }
    )
    return initFunc
}
js.Global().Set("initSandpiles", initSandpilesWrapper())

The break down:

js.Func is a function that can be accessed by JS
js.FuncOf() turns a Go function into a js.Func
js.Value is important because we need to Go-ify anything that comes in
we would like to have the global 'this' and local 'args' please

Issues

Return types on Go js.FuncOf()

Not all Go data structures can be returned via the interface{} return type in js.FuncOf() For example:

No multidimensional slices
In fact, no slices at all D:`

I kinda suck at Go

My weak dynamically typed brain demands satisfaction. I just made the variable in this function, it's not changing while we run, I swear. Really please let me use it as a const. Pretty please!? Wait, okay then, Go devs must turn slices into arrays all the time. No? What, why is this so hard to google? copy(varLead.Magic[:], someSlice[0:4]) Does this operation really merit the word 'Magic'? Okay I can just loop and load an array, but not dynamically, we'll try the magic thing later. Only nerds use []byte, I'm sticking with []int

Time for dependencies!

I am going to try @markfarnan/go-canvas behold the monstrosity of typecasting

s.piles[row+1][col] += int(math.Floor(float64(s.toppleThreshold) / 4))

Performance is not great on canvas...

Fully functioning!

Web Canvas API is the bottleneck. There is mention of using goroutines to avoid this. Go can log like a champ. Logging in JS can really load up the event loop .Truthy() is js derpiness leaking in to Go interop

snoogans775/wasm-sandpiles