Avoid duplicated records in a key, value structure JS

Question

An easy question from a noob.

I have this example where I create a list with a Key/Value structure, I use the Id as the Key and the rest of the content is the value so if I add more records they will be added to my list $scope.itemList [ ]

var data = [
              {
                id: 1,
                name : "Peter",
                lastname : "Smith",
                age : 36
              }, {
                id: 2,
                name : "Peter",
                lastname : "Smith",
                age : 36
              }
            ];

            $scope.itemList = [];
            angular.forEach(data, function(item){
                var obj = {};
                var valObj = {};

                valObj.name = item.name;
                valObj.lastname = item.lastname;
                valObj.age = item.age;

                obj[item.id] = valObj;
                $scope.itemList.push(obj);
            });

The thing is that I could have more records in my json with the same id and I want to avoid adding duplicated records, now this code will push everything it comes in it without matter if the id's are duplicated, but I dont know how to compare the var obj {} with the item.id, I tried different "options" but none of them work.

Some help on this will be great and I'll appreciate it a lot

Hi, obj is to store the value coming from the ID that is my "key" and valObj stores the rest of the record in my json (name, lastname and age) as the "value" — kennechu, May 24 '16 at 01:44
http://stackoverflow.com/a/36236204/5149381 or take a look at [Angular-Filter](https://github.com/a8m/angular-filter) — litel, May 24 '16 at 01:53

Neta Meta · Answer 1 · 2016-05-24T02:16:50.970

Solution

var data = [
  {
    id: 1,
    name : "Peter1",
    lastname : "Smith",
    age : 36
  }, {
    id: 2,
    name : "Peter2",
    lastname : "Smith",
    age : 36
  }, {
    id: 2,
    name : "Peter3",
    lastname : "Smith",
    age : 36
  }
];

$scope.itemList = [];
angular.forEach(data, function(item){
  var obj = {};
  var valObj = {};

  valObj.name = item.name;
  valObj.lastname = item.lastname;
  valObj.age = item.age;

  if ( !obj[item.id]) {
    obj[item.id] = valObj;
    $scope.itemList.push(obj);
  }

});

however if you dont have a very good reason for obj[item.id] then you should be looking at findIndex of lodash or something like that.

I mean i cant see a reason why you would have to have 2 separate objects like that.

update

var data = [
  {
    id: 1,
    name : "Peter1",
    lastname : "Smith",
    age : 36
  }, {
    id: 2,
    name : "Peter2",
    lastname : "Smith",
    age : 36
  }, {
    id: 2,
    name : "Peter3",
    lastname : "Smith",
    age : 36
  }
];

$scope.itemsList = [];
angular.forEach(data, function(item){
  if(_.findIndex($scope.itemsList, function(itemList){ return item.id === itemList.id }) === -1){
    $scope.itemsList.push(item);
  }
});

Thanks a lot for your time.. So what is a better option to avoid using two objects, I mean, I made it this way because it works for me, I got the expected result but if there's a way to optimize it I open because Im learning =) — kennechu, May 24 '16 at 02:07
Check the update, - using lodash, you can easily make a function that replaces _.findIndex — Neta Meta, May 24 '16 at 02:17

score 1 · Accepted Answer · answered May 24 '16 at 02:09

If you changed the itemList from a list to a dictionary, I think it would do what you need. Something like:

var data = [
              {
                id: 1,
                name : "Peter",
                lastname : "Smith",
                age : 36
              }, {
                id: 2,
                name : "Peter",
                lastname : "Smith",
                age : 36
              }
            ];

            $scope.itemDictionary = {};
            angular.forEach(data, function(item){
                var obj = {};
                var valObj = {};

                valObj.name = item.name;
                valObj.lastname = item.lastname;
                valObj.age = item.age;

                obj[item.id] = valObj;
                if(!$scope.itemDictionary[item.id]){
                     $scope.itemDictionary[item.id] = obj;
                }
            });

Hi bwyn, I wich moment in this code you "push" the data, it works, I already test it because I log the result, but I dont get when this happen. — kennechu, May 24 '16 at 06:01

Avoid duplicated records in a key, value structure JS

2 Answers2