//the authors let authors = [ { name: 'J.K. Roaring', books: [ { title: 'The Philosepher\'s Kidney Stone' }, { title: 'The Chamber Pot of Secrets' }, { title: 'The Prisoner of Aunt Kazban' }, { title: 'The Goblet of the Fire Cocktail' }, { title: 'The Order for Kleenex' }, { title: 'The Half-Priced Pharmacy' }, { title: 'Yeah, I Got Nothing' }, ] }, { name: 'Kenneth Grahame', books: [ { title: 'The Wind in the Willows', published: '1 April 1908' } ] }, { name: 'Kayne Ruse', books: [ { title: 'alpha', published: "1" }, { title: 'beta', published: "2" }, { title: 'gamma', published: "3" }, { title: 'delta', published: "4" }, { title: 'epsilon', published: "5" }, ] }, ]; //insert the authors into the books (relationship) authors = authors.map(a => { a.books = a.books.map(b => { b.author = a; return b; }); return a; }); //get the books array let books = []; authors.forEach(a => books = books.concat(a.books)); //the fake database module.exports = { authors, books, };