Why map does not work under Tracker.autorun of Meteor?

Question

Recently I found out that if I apply the map function to my array inside Meteor's Tracker.autorun function it does not work, I have been wondering why? I tried making static array even that doesn't work.

   renderMyBooks() {
        Tracker.autorun(() => { 
            Meteor.subscribe("ziglerNata")
            console.log(Meteor.userId());
            const myBooks = BooksInfo.find({ userId: Meteor.userId() }).fetch();
            //const myBooks = [1,2,3,4,5];
            console.log(myBooks);
            return (myBooks.map(book => {
                    return (
                        <div key={book._id} className="book-info">
                            <div className="book-info-content">
                                <div className="book-info-content-t-a">
                                    <h3>{book.title} </h3>
                                    <h5>{book.author}</h5>
                                </div>
                                
                            </div>
                        </div>
                    )
                })
            )
        })
    }

Answer 1

I would suggest a different approach. This may not directly answer your question as to why Tracker.autorun is not working as you expected, but I think will help you more than if looking for an answer to your original question.

I believe the recommended pattern for using reactive data sources in meteor with react is to use useTracker. Here is your code rewritten in that pattern:

import { useTracker } from 'meteor/react-meteor-data';

const MyBooks = () => {
  const myBooks = useTracker(() => {
    Meteor.subscribe("ziglerNata")
    console.log(Meteor.userId());
    return BooksInfo.find({ userId: Meteor.userId() }).fetch();
  }, []);

  console.log(myBooks);
  return (myBooks.map(book =>
    <div key={book._id} className="book-info">
      <div className="book-info-content">
        <div className="book-info-content-t-a">
          <h3>{book.title} </h3>
          <h5>{book.author}</h5>
        </div>
      </div>
    </div>
  ));
}