Was I wrong to use spread operator here?

JavaScript
1

So I wrote:

// The global variable
var bookList = ["The Hound of the Baskervilles", "On The Electrodynamics of Moving Bodies", "Philosophiæ Naturalis Principia Mathematica", "Disquisitiones Arithmeticae"];

// Change code below this line
function add (bookName) {
  let newList = [...bookList]; 
  newList.push(bookName);
  return newList;
  
  // Change code above this line
}

// Change code below this line
function remove (bookName) {
  var book_index = bookList.indexOf(bookName);
  let newList = [...bookList]; 
  if (book_index >= 0) {

    newList.splice(book_index, 1);
    return newList;

    // Change code above this line
    }
}

var newBookList = add(bookList, 'A Brief History of Time');
var newerBookList = remove(bookList, 'On The Electrodynamics of Moving Bodies');
var newestBookList = remove(add(bookList, 'A Brief History of Time'), 'On The Electrodynamics of Moving Bodies');

console.log(bookList);
2

You need to add bookList as your first argument.

They are calling the functions with bookList as the first argument so what you think is bookName is actually bookList

3

So spread operator was right I just had to change parameters?

4

Yes, your code works fine given the parameters are in the right order.

They do make a note of it, but I think their choice as to what they start your code off with makes it unnecessarily confusing.

5

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