getBooksPossessedByAccount()

solution.js

function getBooksPossessedByAccount(account, books, authors) {
  //Initialze a return array
  let booksPossessed=[];
  //check for the account id in the borrows arrays
  books.forEach(book => {
    let borrowArray = book.borrows;
    if (borrowArray.find(borrow => borrow.id === account.id && borrow.returned === false)) {
      booksPossessed.push(book);
    }
  })
  
  booksPossessed.forEach(book=>{
    let author = authors.find(person => person.id === book.authorId);
    book['author'] = author;
  })
  console.log(booksPossessed);
  return booksPossessed;
  
}

function getBooksPossessedByAccount(account, books, authors) {
  let accountID = account.id;
  let borrowed = [];
  for (let i = 0; i < books.length; i++)
  {
    for (let j = 0; j< books[i].borrows.length; j++)
    {
      if (books[i].borrows[j].id == account.id && books[i].borrows[j].returned == false){
        borrowed.push(books[i]);
      }
    }
  }
  return borrowed;
}