723_promise问题_then返回结果

<script>
      let p = new Promise((resolve, reject) => {
        resolve("OK");
      });

      let result = p.then(
        (value) => {
          //1、抛出错误
          //throw "出错了"
          //2、返回结果是一个非Promise对象,结果为fulfilled
          //return 521;
          //3、返回结果是一个Promise对象，结果由Promise对象决定
          return new Promise((resolve, reject) => {
            reject("123");
          });
        },
        (reason) => {
          console.log(reason);
        }
      );
      console.log(result);
    </script>