Function threads

packages/core/src/threading/threads.ts:56–109

(
  factory: ThreadsFactory,
  callback?: ThreadsCallback,
)

 *                   Used for debugging purposes.
 */
export function* threads(
  factory: ThreadsFactory,
  callback?: ThreadsCallback,
): ThreadGenerator {
  const playback = usePlayback();
  const root = factory();
  setTaskName(root, 'root');
  const rootThread = new Thread(root);
  callback?.(rootThread);

  let threads: Thread[] = [rootThread];
  while (threads.length > 0) {
    const newThreads = [];
    const queue = [...threads];
    const dt = playback.deltaTime;

    while (queue.length > 0) {
      const thread = queue.pop();
      if (!thread || thread.canceled) {
        continue;
      }

      const result = thread.next();
      if (result.done) {
        thread.cancel();
        continue;
      }

      if (isThreadGenerator(result.value)) {
        const child = new Thread(result.value);
        thread.value = result.value;
        thread.add(child);

        queue.push(thread);
        queue.push(child);
      } else if (result.value) {
        thread.value = yield result.value;
        queue.push(thread);
      } else {
        thread.update(dt);
        thread.drain(task => {
          const child = new Thread(task);
          thread.add(child);
          newThreads.unshift(child);
        });

        newThreads.unshift(thread);
      }
    }

    threads = newThreads.filter(thread => !thread.canceled);
    if (threads.length > 0) yield;
  }
}