Remove Duplicates From An Array Of Objects Using JavaScript

Diptiranjan Sutar
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Introduction

We can remove duplicates from an array of objects using the following methods,

Using Set and Array.from() method

This method involves converting the array of objects into a Set object, automatically removing duplicates, and then converting it back into an array using Array.from().

let arr = [{
    id: 1,
    name: 'John'
}, {
    id: 2,
    name: 'Jane'
}, {
    id: 1,
    name: 'John'
}];
let uniqueArray = Array.from(new Set(arr.map(JSON.stringify))).map(JSON.parse);

Using filter() method

This method uses the filter() method to iterate over the array of objects and check if the current object already exists in a new array. If it doesn't, it is added to the new array.

let arr = [{
    id: 1,
    name: 'John'
}, {
    id: 2,
    name: 'Jane'
}, {
    id: 1,
    name: 'John'
}];
let uniqueArray = arr.filter((obj, index, self) => index === self.findIndex((t) => (t.id === obj.id && t.name === obj.name)));

Using reduce() method

This method uses the reduce() method to iterate over the array of objects and check if the current object already exists in a new array. If it doesn't, it is added to the new array.

let arr = [{
    id: 1,
    name: "John"
}, {
    id: 2,
    name: "Jane"
}, {
    id: 3,
    name: "John"
}, {
    id: 4,
    name: "Jane"
}];
let uniqueArr = arr.reduce((acc, current) => {
    let exists = acc.some(item => item.id === current.id && item.name === current.name);
    if (!exists) {
        acc.push(current);
    }
    return acc;
}, []);
console.log(uniqueArr);

These are the many ways to remove duplicates from an array of objects.