WebAssembly.Module is [Serializable] except *forStorage*

[petamoriken]

Deno KV can store [Serializable] values. WebAssembly.Module is [Serializable], but it is only supposed to be used for postMessage and is not allowed to be stored in storage.

The serialization steps, given value, serialized, and forStorage, are:

1. If forStorage is true, throw a "DataCloneError" DOMException.
2. Set serialized.[[Bytes]] to the sub-serialization of value.[[Bytes]].
3. Set serialized.[[AgentCluster]] to the current Realm's corresponding agent cluster.

https://webassembly.github.io/spec/web-api/index.html#serialization

---

So the following code should throw a DataCloneError.

const importObject = {
  imports: { imported_func: (arg) => console.log(arg) },
};
const { module } = await WebAssembly.instantiateStreaming(
  fetch("https://mdn.github.io/webassembly-examples/js-api-examples/simple.wasm"),
  importObject,
);

const kv = await Deno.openKv();
await kv.set(["module"], module);
// => { ok: true, versionstamp: "00000000000000020000" }

And apparently, when I try to restart Deno and retrieve the value, I get a RangeError.

const kv = await Deno.openKv();
await kv.get(["module"]);
// Uncaught RangeError: could not deserialize value
//     at Object.deserialize (ext:core/01_core.js:490:43)
//     at deserializeValue (ext:deno_kv/01_db.ts:251:29)
//     at Kv.get (ext:deno_kv/01_db.ts:37:16)
//     at async <anonymous>:2:1