Comment by modeless

Huh, no types. So every field is 8 bytes I guess?

I suppose if you want a defined/packed memory layout you can already use SharedArrayBuffer and if you want to store objects in it you can use this BufferBackedObjects library they linked. https://github.com/GoogleChromeLabs/buffer-backed-object

I also expect that in browsers this will have the same cross-origin isolation requirements as SharedArrayBuffer that make it difficult to use.