How to check if an array includes an object in JavaScript ?
In JavaScript, an array acts like like list. It’s a way to group multiple items together under one name. You can store different things in your list, like numbers, words, or even other lists. Each item in the list has its own place, and you can access it using a number called its “index.”
We will check if an array includes an object or not in JavaScript. There are various methods to check whether an array includes an object or not.
How to check if an array includes an object in JavaScript ?
These are the following approaches by using these we can check if an array includes an object in JavaScript:
Table of Content
- Using includes() Method
- Using some() Method
- Using filter() Method
- Using findIndex() Method
- Using Lodash _.find() Method
- Using the spread operator (…) and Math.floor():
- Using Array.prototype.find Method
Using includes() Method
If the array contains an object/element can be determined by using the includes() method. This method returns true if the array contains the object/element else return false.
Syntax:
array.includes( element/object, startingPosition )
Example: This example shows the use of the above-explained approach.
let obj = { "Beginner1": 10, "Beginner2": 12 }
let gfg = ["Beginner1", "Beginner2", obj];
// Use JavaScript includes() method
let num = gfg.includes(obj, 0);
console.log(num)
Output
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: This example shows the use of the above-explained approach.
let arr = ["Beginner1", "Beginner2", "Beginner3",
{ 1: "Beginner4", 2: "Beginner5" }];
let boolVar = arr.some(
value => { return typeof value == "object" });
console.log(boolVar);
Output
true
Using filter() Method
The filter() method creates the array of all those elements/objects that pass the checking condition.
Syntax:
array.filter( function(currValue, arrIndex, arrObj), this )
Example: This example shows the use of the above-explained approach.
let obj = { "Beginner1": 10, "Beginner2": 12 }
let arr = ["Beginner1", "Beginner2", "Beginner3", obj];
if (arr.filter(value => value == obj).length > 0)
console.log("true");
else
console.log("false");
Output
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: This example shows the use if the above-explained approach.
let arr = ["Beginner1", "Beginner2", "Beginner3",
{ "Beginner1": 10, "Beginner2": 12 }];
let num = arr.findIndex(
value => { return typeof value == "object" });
console.log("Object found at position: " + num);
Output
Object found at position: 3
Using Lodash _.find() Method
we are using _.find() method which helps us to find out that the given value is present in the array or not. and lodash is third party and javascript library.
Syntax:
_.find(collection, predicate, [fromIndex=0])
Example: This example shows the use if the above-explained approach.
// Requiring the lodash library
const _ = require("lodash");
// Collection of string
let arr = ["Beginner1", "Beginner2", "Beginner3",
{ "Beginner1": 10, "Beginner2": 12 }];
let obj = { "Beginner1": 10, "Beginner2": 12 }
// Check value is found
// or not by _.includes() method
console.log(_.find(arr, obj));
Output:
{ "Beginner1": 10, "Beginner2": 12 }
Using the spread operator (…) and Math.floor():
In this approach, we utilize the spread operator (…) to create a copy of the original array. Then, we generate a random index within the range of the array length using Math.floor() and Math.random(). Finally, we return the randomly selected element from the copied array.
Example: In this example The function getRandomElement() returns a randomly selected element from an array by creating a copy, generating a random index, and accessing the element at that index.
let arr = ["apple", "banana", "orange", "grape", "kiwi"];
function getRandomElement(arr) {
// Create a copy of the original array using the spread operator
let copyArr = [...arr];
// Generate a random index within the range of the array length
let randomIndex = Math.floor(Math.random() * copyArr.length);
// Return the randomly selected element
return copyArr[randomIndex];
}
console.log(getRandomElement(arr));
Output
grape
Using Array.prototype.find Method
Another approach to check if an array includes an object in JavaScript is by using the find method. This method iterates over the array and returns the first element that satisfies the provided testing function. If no elements satisfy the testing function, it returns undefined.
Example: In this example, we will use the find method to check if the array includes the specified object.
let obj = { "Beginner1": 10, "Beginner2": 12 };
let arr = ["Beginner1", "Beginner2", "Beginner3", obj];
// Use JavaScript find() method
let found = arr.find(element => element === obj);
if (found !== undefined) {
console.log("Object found in the array");
} else {
console.log("Object not found in the array");
}
Output
Object found in the array
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