[isolated-workers] Have ability to call dispose on classes when destroyed for v1?

[bfgeek]

E.g.

[NoInterfaceObject]
interface Disposable {
  void dispose(); 
};

Spec wording:
Creating classes registered on the global scope is the responsibility user agent. To allow authors to release resources used by these classes, the user agent must call the dispose() method on the class before destroying.

The only use-case for this is shared cache-objects on the global scope, and allowing code to clean up after themselves. Is it worth putting this in v1?

E.g.

var sharedCache = null;
var sharedCacheCount = 0;
registerAClass('foo', class Foo {
  constructor() {
    sharedCacheCount++;
    if (!sharedCache) buildExpensiveCache();
  },
  dispose() {
    sharedCacheCount--;
    if (!sharedCacheCount) sharedCache = null; // Frees memory.
  }
});

[domenic]

Doesn't this violate https://w3ctag.github.io/design-principles/#js-gc

[bfgeek]

Maybe, it doesn't explicitly tell you when gc is going to occur, just "I'm never ever going to invoke you of your methods again". ¯\o/¯

[esprehn]

This is similar life cycle management as attachedCallback/detachedCallback in custom elements. dispose is the isolated worker side callback that would fire for detachedCallback.

[bfgeek]

It was decided that we should leave this type of API until V2 of worklets / paint.