aco.ts

// aco -- Async COmmunication system
export interface Action {
  event: Event;
  value: any;
  tag?: string;
}

let tmp: Action | null = null;

export const send = (value: any, tag?: string) => (event: Event) => {
  const a: Action = { event, value, tag };
  if (tmp === null) {
    tmp = a;
    return;
  }

  const poll = () => {
    if (tmp === null) {
      tmp = a;
      return;
    }
    requestAnimationFrame(poll);
  };
  requestAnimationFrame(poll);
};

export const recv = async (tag?: string): Promise<Action> => {
  return new Promise(resolve => {
    const poll = () => {
      if (tmp !== null && (tag === undefined ? true : tag === tmp.tag)) {
        const res = tmp;
        tmp = null;
        resolve(res);
        return;
      }
      requestAnimationFrame(poll);
    };
    requestAnimationFrame(poll);
  });
};