export class Thread<R, F extends (...args: any[]) => R> {
  private _worker: Worker;

  constructor(fn: F) {
    const stringFn = `self.onmessage = (event) => {
      const data = event.data;
      const fn = ${fn.toString()};
      const result = fn(...data.data);
      self.postMessage(result);
    }`;
    const jsFile = new File([stringFn], `${fn.name}.js`, { type: "application/javascript" });
    const jsFileUrl = URL.createObjectURL(jsFile);
    this._worker = new Worker(jsFileUrl);
  }

  public run(...args: Parameters<F>): Promise<R> {
    this._worker.postMessage({ data: [...args] });
    return new Promise<R>((res, rej) => {
      this._worker.addEventListener("message", (event) => res(event.data));
      this._worker.addEventListener("error", (event) => rej(event));
    });
  }

  public terminate(): void {
    this._worker.terminate();
  }
}