Class TasksV2Store

src/hooks/useTasksV2.ts:29–199

* Singleton store for the TodoV2 task list. Owns the file watcher, timers, * and cached task list. Multiple hook instances (REPL, Spinner, * PromptInputFooterLeftSide) subscribe to one shared store instead of each * setting up their own fs.watch on the same directory. The Spinner mounts/ * unmou

 * Implements the useSyncExternalStore contract: subscribe/getSnapshot.
 */
class TasksV2Store {
  /** Stable array reference; replaced only on fetch. undefined until started. */
  #tasks: Task[] | undefined = undefined
  /**
   * Set when the hide timer has elapsed (all tasks completed for >5s), or
   * when the task list is empty. Starts false so the first fetch runs the
   * "all completed → schedule 5s hide" path (matches original behavior:
   * resuming a session with completed tasks shows them briefly).
   */
  #hidden = false
  #watcher: FSWatcher | null = null
  #watchedDir: string | null = null
  #hideTimer: ReturnType<typeof setTimeout> | null = null
  #debounceTimer: ReturnType<typeof setTimeout> | null = null
  #pollTimer: ReturnType<typeof setTimeout> | null = null
  #unsubscribeTasksUpdated: (() => void) | null = null
  #changed = createSignal()
  #subscriberCount = 0
  #started = false

  /**
   * useSyncExternalStore snapshot. Returns the same Task[] reference between
   * updates (required for Object.is stability). Returns undefined when hidden.
   */
  getSnapshot = (): Task[] | undefined => {
    return this.#hidden ? undefined : this.#tasks
  }

  subscribe = (fn: () => void): (() => void) => {
    // Lazy init on first subscriber. useSyncExternalStore calls this
    // post-commit, so I/O here is safe (no render-phase side effects).
    // REPL.tsx keeps a subscription alive for the whole session, so
    // Spinner mount/unmount churn never drives the count to zero.
    const unsubscribe = this.#changed.subscribe(fn)
    this.#subscriberCount++
    if (!this.#started) {
      this.#started = true
      this.#unsubscribeTasksUpdated = onTasksUpdated(this.#debouncedFetch)
      // Fire-and-forget: subscribe is called post-commit (not in render),
      // and the store notifies subscribers when the fetch resolves.
      void this.#fetch()
    }
    let unsubscribed = false
    return () => {
      if (unsubscribed) return
      unsubscribed = true
      unsubscribe()
      this.#subscriberCount--
      if (this.#subscriberCount === 0) this.#stop()
    }
  }

  #notify(): void {
    this.#changed.emit()
  }

  /**
   * Point the file watcher at the current tasks directory. Called on start