javascript - Can mongoose not use the obtained ajax data as query conditions?

Question

Ques.find({'author': 'admin'})
    .select('star')
    .exec((err, stars) => {
      if (err) next(err)
      console.log(stars)
    });

Writing directly in this way can obtain the data whose author is admin.

But when changing to ajax data, it never works

  let authors = req.body.author;
  console.log("服务器收到一个Ajax请求，信息为：", authors);
  console.log(typeof(authors))  // string
  let auth = authors 
  console.log(auth)  // admin
  Ques.find({'author': auth})
    .select('star')
    .exec((err, stars) => {
      if (err) next(err)
      console.log(stars)
    });

No data is displayed, indicating that the user was not found

I tried this again

  let auth = 'admin'
  Ques.find({'author': auth})
    .select('star')
    .exec((err, stars) => {
      if (err) next(err)
      console.log(stars)
    });

This is also possible

ajax request

      let author = XXX; // 动态获取的
      $.ajax({
        data: {author: author},
        url: '/star',
        dataType: 'json',
        timeout: 2000,
        type: "POST",
        success: function(data){
          console.log(data);
        }
      });

Answer 1

For reference. Because it is called by AJAX, the results are returned to the calling place for display instead of console printing.

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