How do I instantiate an object with a string extracted from input?

Question

I have an input area in my HTML.

<input id="bookTitle" type="text">

Now, my javascript look like this:

function Book(title){
  this.title = title;
}

function addToLibrary(){
  const title = document.querySelector("#bookTitle").value;
  const book = new Book(title) // replace the book variable name with the value of title
}

How do I make it so that the instead of the instantiating Book Class with variable book, I instantiate it with the value of title itself.

For Example,

If my input has value "Hobbit", I want Hobbit to be the variable name instead of book.