How to compare two objects and remove the duplicate objects by value in javascript

Question

I am having two objects i would like to compare those objects and remove the duplicate objects by value and show the rest of the objects.I have tried lodash omit but it doesn't works.

    let users = [
  {value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},
  {value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},
  {value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},
  {value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},
  {value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},
  {value: "ObQhbfH3YroudLVz5YkY", label: "User10"}
]

let selectedUsers = [
{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},
{value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},
{value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},
{value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},
{value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},
{value: "ObQhbfH3YroudLVz5YkY", label: "User10"},
{value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}
]

Without using multiple loops is it possible to remove the duplicates

Why are `users` and `selectedUsers` objects instead of arrays? — David, Oct 29 '18 at 07:43
@HassanImam expected ouput is [{value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}] — Nidhin Kumar, Oct 29 '18 at 07:45
What is the criteria of defining whether objects are duplicate? — Nikhil Aggarwal, Oct 29 '18 at 07:46
Possible duplicate of [Compare two Javascript Arrays and remove Duplicates](https://stackoverflow.com/questions/14930516/compare-two-javascript-arrays-and-remove-duplicates) — David, Oct 29 '18 at 07:47
Possible duplicate of [How to determine equality for two JavaScript objects?](https://stackoverflow.com/questions/201183/how-to-determine-equality-for-two-javascript-objects) — Isaac, Oct 29 '18 at 07:49

score 1 · Answer 1 · answered Oct 29 '18 at 09:55

var userObjectOfObjects = users.reduce(
        (acc, o) => {
            acc[o.value] = o;
            return acc;
        }, {} )

var selectUsersObject = selectedUsers.reduce(
    (acc, o) => {
        if(userObjectOfObjects[o.value]){
            acc.duplicates.push(o)
            return acc;
        }
        else {
            acc.objectWithoutDuplicates.push(o)
        }
        acc.uniqueList[o.value] = o;
        return acc;
    }, { uniqueList: {}, objectWithoutDuplicates:[], duplicates: [] } )


selectUsersObject.uniqueList = {
    ...selectUsersObject.uniqueList,
    ...userObjectOfObjects
}

var uniqueList = Object.values(selectUsersObject.uniqueList)
var duplicates = selectUsersObject.duplicates
var noRepetition = selectUsersObject.objectWithoutDuplicates

score 0 · Answer 2 · answered Oct 29 '18 at 07:51

0

let result = _.unionBy(users, selectedUsers, 'value');

answered Oct 29 '18 at 07:51

Alfred Ayi-bonte

715
7
11

@MatthieuBrucher it essentially returns the unique objects by value. – Alfred Ayi-bonte Oct 29 '18 at 11:53
@MatthieuBrucher I thought that was self-explanatory. – Alfred Ayi-bonte Oct 29 '18 at 11:56

score 0 · Answer 3 · answered Oct 29 '18 at 07:51

You can use differenceWith and isEqual to get the unique value from the selectedUsers.

let users = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"}, {value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"}, {value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"}, {value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"}, {value: "km2jHXDQgPXdBY4jq6dG", label:
"User50"}, {value: "ObQhbfH3YroudLVz5YkY", label: "User10"}],
    selectedUsers = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"}, {value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"}, {value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"}, {value: "WE6kIW8sGkEuMRXQgQPT",
label: "User8"}, {value: "km2jHXDQgPXdBY4jq6dG", label: "User50"}, {value: "ObQhbfH3YroudLVz5YkY", label: "User10"}, {value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}],
    result = _.differenceWith(selectedUsers, users, _.isEqual);
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Dinesh Pandiyan · Answer 4 · 2018-10-29T07:59:56.747

0

Any solution to this would require multiple loops. It's either you write multiple loops or the shorthand code you write uses multiple loops internally.

This one-liner should work for you

const arrWithoutDup = selectedUsers.filter(sUser => users.filter(user => sUser.value === user.value && sUser.value === user.value).length === 0);

edited Oct 29 '18 at 07:59

answered Oct 29 '18 at 07:54

Dinesh Pandiyan

5,814
2
30
49

score 0 · Answer 5 · answered Oct 29 '18 at 07:55

Assuming for objects to duplicate, value and label values should be same.

You can try following using simple Javascript with linear complexity. Firstly, convert users array into an object and then using Array.filter on second array, filter out the duplicate objects.

let users = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},{value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},{value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},{value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},{value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},{value: "ObQhbfH3YroudLVz5YkY", label: "User10"}];
let selectedUsers = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},{value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},{value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},{value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},{value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},{value: "ObQhbfH3YroudLVz5YkY", label: "User10"},{value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}];

let uersObj = users.reduce((a,c) => Object.assign(a, {[c.value]:c.label}), {});
let result = selectedUsers.filter(v => !uersObj[v.value] || uersObj[v.value] !== v.label);
console.log(result);

How to compare two objects and remove the duplicate objects by value in javascript

5 Answers5