lodash - Count duplicate and then remove them

Question

I am trying to use lodash to first count how many duplicates are in an array of objects and the remove the duplicate (keeping the counter).

The code I have so far se

Answer 1

I would use groupBy() to group all items with the same ID into separate arrays, then only keep one from each individual array, setting qty to its length.

const array = [
  {id: 1, name: "test"},
  {id: 2, name: "test 2"},
  {id: 3, name: "test 3"},
  {id: 4, name: "test 4"},
  {id: 1, name: "test "},
  {id: 2, name: "test 2"}
];

const result = _(array).groupBy('id').values().map(
  (group) => ({...group[0], qty: group.length})
);

console.log(result);

Edit Updated to make it shorter, and prevent mutating the original array elements.