Javascript Program to Find the Largest Element in an Array

In this article, we will learn how to find the largest element in an array in JavaScript. An array is a collection of items stored at contiguous memory locations. We have to find the largest element in the array. We can do this by performing many approaches.

Examples:

Input: arr = [10, 20, 4]
Output: 20
Explanation: Among 10, 20 and 4, 20 is the largest. 

Input : arr = [20, 10, 20, 4, 100]
Output : 100

Below are the following approaches through which we find the largest element in an array in JavaScript:

• Using the Brute force Approach
• Using Math.max() and apply() Methods
• Using reduce() Method
• Using sort() Method
• Using Recursion

Javascript Program to Find the Largest Element in an Array using Brute force Approach

• Create a local variable max and initiate it to arr[0] to store the maximum among the list
• Initiate an integer i = 0 and repeat steps 3 to 5 till i reaches the end of the array.
• Compare arr[i] with max.
• If arr[i] > max, update max = arr[i].
• Increment i once.
• After the iteration is over, return max as the required answer.

Example:

Javascript

// JavaScript program to find
// maximum in arr[] of size n

function largest(arr) {
    let i;

    // Initialize maximum element
    let max = arr[0];

    // Traverse array elements
    // from second and compare
    // every element with current max
    for (i = 1; i < arr.length; i++) {
        if (arr[i] > max)
            max = arr[i];
    }

    return max;
}

// Driver code
let arr = [22, 65, 1, 39];
console.log("Largest in given array is " + largest(arr));

Output

Largest in given array is 65

Javascript Program to Find the Largest Element in an Array using Math.max() and apply() Methods

The JavaScript Math max() Method is used to return the largest of zero or more numbers. The result is “-Infinity” if no arguments are passed and the result is NaN if at least one of the arguments cannot be converted to a number. The apply() function allows you to pass an array of arguments to the Math.max() function.

Syntax:

Math.max(value1, value2, ...)

Example:

Javascript

function LargestElement(arr) {
    if (arr.length === 0) {
        console.log("Array is empty");
    }

    return Math.max.apply(null, arr);
}
const arr = [22, 65, 1, 39];
console.log("Largest in given array is " + LargestElement(arr));

Output

Largest in given array is 65

Javascript Program to Find the Largest Element in an Array using reduce() Method

The Javascript arr.reduce() method in JavaScript is used to reduce the array to a single value and executes a provided function for each value of the array (from left to right) and the return value of the function is stored in an accumulator. 

Syntax: 

array.reduce( function(total, currentValue, currentIndex, arr), 
initialValue )

Example:

Javascript

function LargestElement(arr) {
    if (arr.length === 0) {
        console.log("Array is empty");
    }

    return arr.reduce(function (a, b) {
        return (a > b) ? a : b});

}
const arr = [22, 65, 1, 39];
console.log("Largest in given array is " + LargestElement(arr));

Output

Largest in given array is 65

Javascript Program to Find the Largest Element in an Array using sort() Method

The Javascript array.sort() is an inbuilt method in JavaScript that is used to sort the array. An array can be of any type i.e. string, numbers, characters, etc. Here array is the set of values that are going to be sorted. 

Syntax:

array.sort()

Example:

Javascript

function LargestElement(arr) {
    if (arr.length === 0) {
        console.log("Array is empty");
    }

    arr.sort((a, b) => b - a);
    return arr[0];
}
const arr = [22, 65, 1, 39];
console.log("Largest in given array is " + LargestElement(arr));

Output

Largest in given array is 65

Javascript Program to Find the Largest Element in an Array using Recursion

• Create a recursive function.
• Set an integer i = 0 to denote the current index being searched.
• Return steps 4 to 7 to get the final answer.
• If i is the last index, return arr[i].
• Increment i and call the recursive function for the new value of i.
• Compare the maximum value returned from the recursion function with arr[i].
• Return the max between these two from the current recursion call.

Example:

Javascript

// JS program to find maximum
// in arr[] of size n
function largest(arr, n, i) {
    // last index
    // return the element
    if (i == n - 1) {
        return arr[i];
    }

    // find the maximum from rest of the array
    let recMax = largest(arr, n, i + 1);

    // compare with i-th element and return
    return Math.max(recMax, arr[i]);
}

// Driver Code
const arr = [22, 65, 1, 39];
const n = arr.length;
console.log("Largest in given array is", largest(arr, n, 0));

Output

Largest in given array is 65