Imagine that you want to buy DVDs for all the Star Wars movies of the original trilogy. (For all the prequel and sequel lovers, this scenario works as well with more movies.) You search Ebay and end up with a list of auctions, each with a different price and each containing a certain subset of the three movies.
const auctions = [
{ id: 1, price: 11, movies: ["NEW_HOPE"] },
{ id: 2, price: 13, movies: ["EMPIRE_STRIKES_BACK"] },