Comparing the performance of recursive and looped factorial function in JavaScript

We will be writing two JavaScript functions, the job of both the functions will be to take in a number and return its factorial.

The first function should make use of a for loop or while loop to compute the factorial. Whereas the second function should compute the factorial using a recursive approach.

Lastly, we should compare the times taken by these functions over a large number of iterations.

Example

Following is the code −

const factorial = (num = 1) => {    let result = 1;    for (let i = 2; i <= num; i += 1) {       result *= i;    }    return result; } const factorialRecursive = (num = 1) => {    if(num > 1){       return num * factorialRecursive(num - 1);    }else{       return 1;    } }; const ITERATIONS = 100000000; const num = 12; console.time('Looping Approach'); for(let i = 0; i < ITERATIONS; i++){    factorial(num); }; console.timeEnd('Looping Approach'); console.time('Recursive Approach'); for(let j = 0; j < ITERATIONS; j++){    factorialRecursive(num); }; console.timeEnd('Recursive Approach');

Output

Following is the output on console −

Looping Approach: 886.720ms Recursive Approach: 6526.203ms

This time taken will vary from machine to machine by the ratio is bound to remain more or less the same.