[wibagusto]

So the workaround is to initialize WASM with an array buffer which allows direct manipulation of the data in WASM it seems. The canvas bytes can be used in WASM so long as the bytes are passed in at initialization.

In that case, JavaScripts only duty is to pack input data into the byte array and pass control to WASM which writes to an output buffer (also shared byte array) and passes control back to JavaScript to process result avoiding an unnecessary data copy.

You’d have to have some types in JS which can process the data using bit shifts and whatnot though in a lower level way.