Basic JavaScript - Replace Loops using Recursion

JavaScript
1

Can someone please help me with this question. I don’t think I understand the question at all.

I saw someone in another thread break down the question but it has since closed. they used the below formula as a way to explain. Could someone explain the `return arr[n - 1] * multiply(arr, n - 1) part to me? I dont understand why I have to multiply the array by itself?

var myArr = [1,2,3,4]

function multiply(arr, n) {

if (n <= 0) {

  return 1;

} else {

  return arr[n - 1] * multiply(arr, n - 1); // look at this

}
}

console.log(multiply(myArr, 4))

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Challenge: Basic JavaScript - Replace Loops using Recursion

Link to the challenge:

4

here’s a link to that thread HOW is `multiply(arr, n) == multiply (arr, n - 1) * arr[n - 1]`? - #6 by Jedidiah.

I understand that I do 4x3x3x1 to get the answer but I dont understand what that one line of code is saying.

5

if you add some console.log(), it helps to understand.

console.log(`n = ${n} , return 1`)

console.log(`n = ${n} , ${arr[n - 1]} * multiply(arr, ${n - 1})}`)

You can see :
image

Result :
4 * 3 * 2 * 1 * 1
= 24

6

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