typesctipt 報錯 Property 'format' does not exist on type 'Date'.

  public getAllDay (begin: any, end: any) {
    const dateAllArr = new Array();
    const ab = begin.split('-');
    const ae = end.split('-');
    const db = new Date();
    db.setUTCFullYear(ab[0], ab[1] - 1, ab[2]);
    const de = new Date();
    de.setUTCFullYear(ae[0], ae[1] - 1, ae[2]);
    const unixDb = db.getTime();
    const unixDe = de.getTime();
    for (let k = unixDb; k <= unixDe;) {
       dateAllArr.push((new Date(parseInt(k))).format().toString());
       k = k + 24 * 60 * 60 * 1000;
    }
    return dateAllArr;
  }

請問怎么解決