JavaScript Program to Search an Element in an Array

We are going to discuss how can we search for an element in an Array using JavaScript. If the given element is present in the array then we will return their index else we will return -1.

Following are the ways to search for an element in an array:

Approach 1: Using Recursive Approach

The recursive approach in JavaScript for binary search involves dividing the array recursively until finding the target element or exhausting the search space, returning the element’s index or -1 accordingly.

Example: The function recursively applies binary search to locate the target element within a sorted array, returning its index if found, or -1 if not present, with efficient time complexity.

Javascript

function SearchingFunction(arr, target, low = 0, high = arr.length - 1) {
    if (low > high) return -1;

    let mid = Math.floor((low + high) / 2);

    if (arr[mid] === target) return mid;
    else if (arr[mid] < target)
        return SearchingFunction(arr, target, mid + 1, high);
    else
        return SearchingFunction(arr, target, low, mid - 1);
}

const array = [10, 20, 30, 40, 50, 60];
const targetElement = 30;
const result = SearchingFunction(array, targetElement);
console.log(`The index of ${targetElement} is: ${result}`);

Output

The index of 30 
is: 2

Approach 2: Using Array.reduce() method

The binary search is implemented with Array.reduce() iterates through the array, accumulating results. It returns the index of the target element or -1 if not found, with linear time complexity.

Example: The function uses Array.reduce to search for the target element within an array, returning its index if found, or -1 if not present, with linear time complexity.

Javascript

function SearchingFunction(arr, target) {
    return arr.reduce((acc, val, index) => {
        if (acc !== -1) return acc;
        if (val === target) return index;
        return -1;
    }, -1);
}

const array = ["HTML", "CSS", "Javascript", "React", "Redux", "Node"];
const targetElement = "Redux";
const result = SearchingFunction(array, targetElement);
console.log(`The index of ${targetElement} is: ${result}`);

Output

The index of Redux is:
 4

Approach 3: Using a for loop:

Using a for loop, iterate through the array elements, comparing each element to the target. If a match is found, return true; otherwise, return false after iterating through all elements.

Example: In this example The searchElement function iterates through an array to find a target element and returns its index if found, otherwise returns -1.

JavaScript

function searchElement(arr, target) {
    for (let i = 0; i < arr.length; i++) {
        if (arr[i] === target) {
            return i; // Return index if found
        }
    }
    return -1; // Return -1 if not found
}

const array = [10, 20, 30, 40, 50, 60];
const targetElement = 30;
const result = searchElement(array, targetElement);
console.log(`The index of ${targetElement} is: ${result}`);

output:

The index of 30 is: 2