const books =[
  {name:'book1',author:'author1 jha'},
  {name:'book2',author:'author2 aha'},
  {name:'book3',author:'author lha'}
];

const sortedBooks = books.sort((book1,book2)=>{
    const authorlastName1 = book1.author.split(' ')[1];
    const authorlastName2 = book2.author.split(' ')[1];
    return authorlastName1 <authorlastName2 ? -1:1;

});
console.log(books);
console.log(sortedBooks);