Get list of duplicate objects in an array of objects

Question

I am trying to get duplicate objects within an array of objects. Let\'s say the object is like below.

values = [
  { id: 10, name: \'someName1\' },
  { id: 1         


        

Answer 1

With lodash you can use _.groupBy() to group elements by their id. Than _.filter() out groups that have less than two members, and _.flatten() the results:

const values = [{id: 10, name: 'someName1'}, {id: 10, name: 'someName2'}, {id: 11, name:'someName3'}, {id: 12, name: 'someName4'}];

const result = _.flow([
  arr => _.groupBy(arr, 'id'), // group elements by id
  g => _.filter(g, o => o.length > 1), // remove groups that have less than two members
  _.flatten // flatten the results to a single array
])(values);

console.log(result);