Finding duplicate objects within an array inside another array. Requires underscore

array-dupe.js

!#/usr/bin/node

var _ = require('underscore');
var duplicates, uniques, temp;

var original = [
                    {"tags": [{_id: ObjectId(1), name: "tag1"}, {_id: ObjectId(2), name: "tag2"}, {_id: ObjectId(3), name: "tag3"}]},
                    {"tags": [{_id: ObjectId(2), name: "tag2"}, {_id: ObjectId(4), name: "tag4"}, {_id: ObjectId(3), name: "tag3"}]},
                    {"tags": [{_id: ObjectId(1), name: "tag1"}, {_id: ObjectId(3), name: "tag3"}, {_id: ObjectId(2), name: "tag2"}]}
                 ];

uniques = [];
temp = [];

_.each(original, function(tagObj) {
  var tags = tagObj.tags;
  _.each(tags, function(tag) {
    if (!_.contains(temp, toString(tag._id))) {
      temp.push(toString(tag._id));
      uniques.push(tag);
    }
  })
});

console.log(temp);
console.log(uniques);


function ObjectId(str) {
  return {"$id": str};
}


function toString(obj) {
  return obj["$id"];
}