atIndex-reframed.js

const arrToManipulate = [3, 5, 9, 2]

const atIndex2 = arr => {
  let total = 1
  const retArr = []
  
  for(let i = 0; i < arr.length; i++) {
    total *= arr[i]
  }

  for(let j = 0; j < arr.length; j++) {
    retArr.push(total / arr[j])
  }

  return retArr
}

atIndex2(arrToManipulate) // [90, 54, 30, 135]