How to remove duplicate objects from an array in JavaScript

by Sai gowtham  1 Min read

In the last tutorial, we have seen how to remove duplicate elements from the array.

We are using es6 map and filter methods to remove the duplicate objects from an array.

Object comparison is done by using the property.

consider we have an array of objects with the id and name but the same id is repeating twice.

const arr = [
  { id: 1, name: "king" },
  { id: 2, name: "master" },
  { id: 3, name: "lisa" },
  { id: 4, name: "ion" },
  { id: 5, name: "jim" },
  { id: 6, name: "gowtham" },
  { id: 1, name: "jam" },
  { id: 1, name: "lol" },
  { id: 2, name: "kwick" },
  { id: 3, name: "april" },
  { id: 7, name: "sss" },
  { id: 8, name: "brace" },
  { id: 8, name: "peiter" },
  { id: 5, name: "hey" },
  { id: 6, name: "mkl" },
  { id: 9, name: "melast" },
  { id: 9, name: "imlast" },
  { id: 10, name: "glow" }
];

Here is my implementation to remove the duplicate objects from an array.

function getUnique(arr, comp) {

  const unique = arr
       .map(e => e[comp])

     // store the keys of the unique objects
    .map((e, i, final) => final.indexOf(e) === i && i)

    // eliminate the dead keys & store unique objects
    .filter(e => arr[e]).map(e => arr[e]);

   return unique;
}

console.log(getUnique(arr,'id')

In the above code, we are using the chaining pattern where the output of the map method will be the input of the other map method.

final array with unique objects

Codepen demo

Happy coding…