text: import { Map } from "immutable";
  
  // Immutable JS provides immutable data-structures (maps, hash-maps)
  
  // let book = { title: "Cuentos de Eva Luna" };
  let book = Map({ title: "Cuentos de Eva Luna" });
  
  function publish(book) {
    return book.set('isPublished', true);
  }
  book = publish(book);
  
  console.log(book);
  console.log(book.get('title'));
  console.log(book.toJS()); // returns plain js object
  
  