@rupertsworld/disposable

A Disposable base class and mixin for objects that own resources: dispose() is made idempotent (the second call is a no-op), a protected disposed flag tracks state, and Symbol.dispose is implemented so instances work with using declarations.

npm install @rupertsworld/disposable

import { Disposable, withDisposable } from "@rupertsworld/disposable";

class Watcher extends Disposable {
  #handle = fs.watch(path, onChange);
  override dispose() { this.#handle.close(); }
}

const w = new Watcher();
w.dispose();
w.dispose(); // no-op

// or with `using`:
{
  using w2 = new Watcher();
} // disposed at block exit

• Disposable — abstract base. Override dispose() (sync or async); the base wraps it so repeated calls run it once, exposes protected get disposed, and implements [Symbol.dispose].
• withDisposable(Base) — the same behavior as a mixin, for classes that already extend something. The subclass must implement dispose().
• DisposableLike — the interface both satisfy: dispose(): void | Promise<void> plus [Symbol.dispose]().
• @rupertsworld/disposable/polyfill — side-effect import that installs Symbol.dispose/DisposableStack globals (via disposablestack) for runtimes that lack them. Import it once at your entry point if needed.

[Symbol.dispose] does not await an async dispose() — using is synchronous disposal; await dispose() yourself when cleanup must complete before continuing.

Changes in 0.2.0

Replaces the 2026-03 0.1.x package (a Disposable interface plus DisposableGroup) with the base-class/mixin design above. For grouped cleanup, use the standard DisposableStack (the /polyfill subpath provides it where missing).