How to check if an array includes an object in JavaScript ?

Check if an array includes an object in JavaScript, which refers to determining whether a specific object is present within an array. Since objects are compared by reference, various methods are used to identify if an object with matching properties exists in the array.

These are the following approaches by using these we can check if an array includes an object in JavaScript:

Using includes() Method

The includes() method checks if an array contains a specific object by reference. It returns true if the exact object reference is found in the array, making it useful when you need to confirm the presence of a specific object instance.

Syntax

array.includes( element/object, startingPosition )

Example: In this example, includes() checks if the object obj is present in the array gfg. It returns true since obj is included, starting the search from index 0.

let obj = { "geeks1": 10, "geeks2": 12 }
let gfg = ["geeks1", "geeks2", obj];

// Use JavaScript includes() method
let num = gfg.includes(obj, 0);

console.log(num)

true

Using some() Method

The some() method uses the function for its evaluation and it executes the function once for each element present in the array. If it finds the object/element in the array then it returns true and stops the execution for the remaining elements otherwise returns false.

Syntax:  

array.some( function(currValue, arrIndex, arrObj), this )

Example: In this example, some() checks if any element in the array arr is an object. It returns true because an object is present in the array.

let arr = ["geeks1", "geeks2", "geeks3",
    { 1: "geeks4", 2: "geeks5" }];

let boolVar = arr.some(
    value => { return typeof value == "object" });

console.log(boolVar);

true

Using findIndex() Method

The findIndex() method returns the position of searched object/element if it is present in the array and stops the execution for the rest elements. If the element/object is not found then return -1.

Syntax: 

array.findIndex( function(currValue, arrIndex, arrObj), this )

Example: In this example, findIndex() returns the index of the first object found in the array arr. The index is logged, showing the object's position within the array.

let arr = ["geeks1", "geeks2", "geeks3",
    { "geeks1": 10, "geeks2": 12 }];

let num = arr.findIndex(
    value => { return typeof value == "object" });

console.log("Object found at position: " + num);

Object found at position: 3

Using Lodash _.find() Method

The Lodash _.find() method searches through an array and returns the first object that matches a specified condition, such as matching properties or deep equality. It’s ideal for complex comparisons and handling nested objects beyond shallow property checks.

Syntax

_.find(collection, predicate, [fromIndex=0])

Example: In this example, _.find() from the Lodash library is used to locate an object within the array arr. If the object matches, it returns the found object.

// Requiring the lodash library 
const _ = require("lodash");

// Collection of string
let arr = ["geeks1", "geeks2", "geeks3",
    { "geeks1": 10, "geeks2": 12 }];
let obj = { "geeks1": 10, "geeks2": 12 }

// Check value is found 
// or not by _.includes() method
console.log(_.find(arr, obj));

Output:

{ "geeks1": 10, "geeks2": 12 }