Javascript es6 - How to remove duplicates in an array of objects, except the last duplicate one?

Question

I have an array:

var arr = [
  {price: 5, amount: 100},
  {price: 3, amount: 50},
  {price: 10, amount: 20},
  {price: 3, amount: 75},
  {price: 7, amount: 1         


        

Answer 1

I'd use reduceRight and splice to remove duplicates. It doesn't create any useless intermediate objects, just a list of unique prices found along the way:

var arr = [
  {price: 5, amount: 100},
  {price: 3, amount: 50},
  {price: 10, amount: 20},
  {price: 3, amount: 75},
  {price: 7, amount: 15},
  {price: 3, amount: 65},
  {price: 2, amount: 34}
]

arr.reduceRight((acc, obj, i) => {
  acc[obj.price]? arr.splice(i, 1) : acc[obj.price] = true;
  return acc;
}, Object.create(null));

arr.sort((a, b) => b.price - a.price);

console.log(arr)