Help with Project Euler 5: Smallest multiple

JavaScript
1

Tell us what’s happening:
So the code is giving me:

[ 1, 2, 3, 2, 5, 1, 7, 2, 3, 1, 11, 2, 13 ]

in prod.

The second last element i.e. 2 should be 1 because 12=223 are already counted. However, due to the way, I’m checking my while(!isPrime(prod[i])) it stops diving prod[i] when it reaches 2 or 3 or whatever prime, but I want it to go all the way to 1.

P.S.: I know it can be done by counting the number of primes and multiplying. I’m wondering if there’s a way like this

Your code so far


function smallestMult(n) {
let prod=[...Array(n).keys()].map(i=>i+1)
let prod2=[...Array(n).keys()].map(i=>i+1)
for(let i=n-1; i>=0; i--)
  do
    for(let j=i-1; j>=0; j--)
      if(prod[i]%prod2[j]==0 && isPrime(prod2[j]))
      {
          prod[i]/=prod2[j]
      }
  while(!isPrime(prod[i]))
let product=1
for(let i=0; i<n; i++)
  product*=prod[i]
console.log(prod)
return product
}

function isPrime(n) {
for(let i=2; i<n; i++)
  if(n%i==0)
    return false
return true
}

smallestMult(13);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; ) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36.

Challenge: Problem 5: Smallest multiple

Link to the challenge:

2

So all numbers that are not primes should have 1 in that array? Are you sure this would give the correct result later?

At that second to last position it isn’t 2 because while loop stopped it sooner. Your for loop doesn’t consider case when one prime can divide number multiple times. It goes like this:

12 / 3 = 4 // j == 2; j--
4  / 2 = 2 // j == 1; j--
2 / 1 = 2 // j == 0; j-- -> end of for loop
3

Not necessarily. I don’t want all non-primes to be 1.

The best way for me to explain what I want is that
12 should be 1 because 12=322 i.e. 34 or 62. Since all these combinations would be covered otherwise too, I want 12 to be 1