How to cancel a pending Atomics.waitAsync?

In several scenarios, after having issued a Atomics.waitAsync(...).value.then((value) => { /* do something */ }); operation, it can happen that some kind of resource/application/page deinitialization type of activity occurs, which deinitializes parts of the Wasm app that contain e.g. the data structures for, say, a lock, semaphore or other multithreading synchronization primitive that resided at that address.

How would one ensure that if such application deinitialization does take place before the waitAsync.then() handler has been invoked, that the promise handler would never be fired (and /* do something */ should never get executed)?

At application level, I can use a separate JavaScript variable

var lockStillExists = true;

void deleteLock() {
  lockStillExists = false;
}

...

Atomics.waitAsync(myInt32Array, ...).value.then((value) => { if (lockStillExists) { /* do something */ } })

to ensure that /* do something */ will never erroneously execute in case the wasm app deinitializes in between, but what happens if I want to deinitialize and let myInt32Array or other JS variables garbage collect altogether? I.e. the promise callback function (value) => { ... } will capture a scope, that would surely pin down myInt32Array and other JS vars in the scope to remain alive indefinitely (since the .then() will never resolve)?

Is there a way to cancel an async wait and/or guarantee that JS garbage collection will safely occur?

Start by reading the Atomics.waitAsync API behavior and the WebAssembly threads proposal context described in the issue. Determine whether async waits have cancellation or garbage-collection guarantees, and document the supported behavior or the design needed to provide safe deinitialization.