JavaScript - Print Object by id in an Array of Objects

Here are the various methods to print objects by id in an array of objects in JavaScript

1. Using Array.filter() Method

The Array.filter() method, creates a new array containing only the object with the specified ID.

//Driver Code Starts
const a = [
    { id: 1, name: "Alia" },
    { id: 2, name: "Dua" },
    { id: 3, name: "Raha" },
    { id: 4, name: "Charu" },
];

//Driver Code Ends

const id = 2;
const result = a.filter(obj => obj.id === id);
console.log(result[0]);

{ id: 2, name: 'Dua' }

In this example

• Array.filter() creates a new array containing objects that meet the condition (obj.id === id).
• Since filter returns an array, [0] is used to access the first matching object.

2. Using for loop

The for loop first we are iterating the array and searching in which object the given id is present and after that, we are printing the property we wanted.

let a = [{ id: 1, name: "a" },{ id: 2, name: "b" },{ id: 3, name: "c" }];

let id = 2;
let prop = "name";
let res = a.find(item => item.id === id);
if (res) console.log(res[prop]);

b

In this example

• The find() method is used to search for the first object in the array where item.id === id.
• Once found, we log the property specified by prop (e.g., "name").

3. Using Underscore.js _.find() Function

The _.find() function looks at each element of the list and returns the first occurrence of the element that satisfy the condition.

const _ = require('underscore');
let a = [{ id: 1, name: "a" }, { id: 2, name: "b" }, { id: 3, name: "c" }];
let id = 2;
let prop = "name";

let obj = _.find(a, { id: id });
console.log(obj?.[prop]);

Output

b

In this example

• _.find(data, { id: id }) simplifies the search by passing an object with id: id instead of using a function.
• obj?.[prop] uses optional chaining to safely access the property, ensuring that it doesn't throw an error if obj is undefined.

4. Using a Map Data Structure

The Map data structure to efficiently store objects by their id as keys.

let a = [{ id: 1, name: "a" }, { id: 2, name: "b" }, { id: 3, name: "c" },];

let map = new Map();
a.forEach(obj => map.set(obj.id, obj));
let reqId = 2;
let reqObj = map.get(reqId);
let reqProp = "name";

console.log(reqObj[reqProp]);

b

In this example

• The code stores objects in a Map using their id as the key.
• It then retrieves an object by its id, and dynamically accesses and prints a specified property (name) of that object using Obj[prop].

devi_johns

Follow

Improve

Article Tags :

• JavaScript
• Web Technologies
• javascript-array
• javascript-object
• JavaScript-Questions

+1 More