Remove original and duplicate from an array of objects - JS

Question

I have an array of objects.

const arr = [
  { title: \"sky\", artist: \"Jon\", id: 1 },
  { title: \"rain\", artist: \"Paul\", id: 2 },
  { title: \"sky\", artis         


        

Answer 1

You can group the items by id, and then use _.flatMap() to convert back a single array. In the _.flatMap() callback return an empty array if the group has more than one item:

const fn = arr => _.flatMap(
  _.groupBy(arr, 'id'), // group by the id
  group => _.size(group) > 1 ? [] : group // check the size and return an empty array for groups with more than a single item
)

const arr1 = [{"title":"sky","artist":"Jon","id":1},{"title":"rain","artist":"Paul","id":2},{"title":"sky","artist":"Jon","id":1}]
const arr2 = [{"title":"sky","artist":"Jon","id":1},{"title":"rain","artist":"Paul","id":2},{"title":"sky","artist":"Jon","id":1},{"title":"rain","artist":"Paul","id":2}]

console.log(fn(arr1))
console.log(fn(arr2))

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