JavaScript Program to Find Remainder of Array Multiplication Divided by n

In JavaScript, the remainder of the array multiplication when divided by the number n can be found by iteration, functional programming or array reduction. , it’s often necessary to calculate the remainder of the product of all elements in an array when divided by a given number ‘n’. There are various possible approaches in JavaScript to achieve this which are as follows:

Table of Content

  • Using forEach() method
  • Using reduce() function
  • Using functional approach with reduce()
  • Using traditional for loop

Using forEach() method

This approach iterates through each element of the array using the forEach() method and calculates the remainder of the product of all elements when divided by a given number ‘n’.

The forEach() method iterates over elements of an array and executes a provided function once for each array element. It allows you to perform a specific action on each element of the array without mutating the array itself.

Example: To demonstrate finding the remainder of the array multiplication using forEach() method.

Javascript




function findRemainder1(arr, n) {
    let product = 1;
    arr.forEach((num) => (product *= num));
    return product % n;
}
 
let arr1 = [3, 7, 2, 5];
let n1 = 11;
console.log(findRemainder1(arr1, n1));


Output

1

Time Complexity: O(n)

Space Complexity: O(1)

Using reduce() function

This method uses the reduce() function to accumulate the product of all array elements and then calculates the remainder when divided by a specified number ‘n’.

The reduce() method executes a reducer function on each element of the array, resulting in a single output value. It accumulates the result of the function calls on each element, providing the final result.

Example: This example illustrates finding the remainder of the array multiplication divided by ‘n’ in JavaScript using the reduce() method.

Javascript




function findRemainder2(arr, n) {
    let product = arr.reduce((acc, val) => {
        acc * val, 1
    });
    return product % n;
}
 
let arr2 = [4, 8, 6, 2];
let n2 = 13;
console.log(findRemainder2(arr2, n2));


Output

NaN

Time Complexity: O(n)

Space Complexity: O(1)

Using functional approach with reduce()

In this approach, a functional programming style is employed along with the reduce() function to find the remainder of the array multiplication when divided by a given number ‘n’.

Example: Here, the code showcases how to find the remainder of the array multiplication divided by ‘n’ in JavaScript using the reduce() method with a functional approach.

Javascript




function findRemainder3(arr, n) {
    return arr.reduce((acc, val) => {
        (acc * val) % n, 1
    });
}
 
 
let arr3 = [1, 2, 3, 4];
let n3 = 17;
console.log(findRemainder3(arr3, n3));


Output

undefined

Time Complexity: O(n)

Space Complexity: O(1)

Using traditional for-loop

This approach utilizes a traditional for-loop to traverse the array and compute the product of all elements, followed by finding the remainder when divided by a provided number ‘n’.

Example: To demonstrates how to find the remainder of the array multiplication divided by ‘n’ in JavaScript using a for loop.

Javascript




function findRemainder4(arr, n) {
    let product = 1;
    for (let num of arr) {
        product *= num;
        product %= n;
    }
    return product;
}
 
let arr4 = [2, 4, 6, 8];
let n4 = 19;
console.log(findRemainder4(arr4, n4));


Output

4

Time Complexity: O(n)

Space Complexity: O(1)