The “WebAssembly object” doesn’t exist as you describe. You probably have an object that wraps WebAssembly function calls and primitive WebAssembly data (indivi

The “WebAssembly object” doesn’t exist as you describe. You probably have an object that wraps WebAssembly function calls and primitive WebAssembly data (individual numbers). WebAssembly functions can only return numbers and can only take numbers as arguments. Everything else is a wrapper that lives in JavaScript. MyNativeButton works exactly as you’d expect. If the GC can clean it up, it might. Otherwise you have a leak that you’d have had in normal JavaScript.