Count of positives / sum of negatives

function countPositivesSumNegatives(input) {
  if(!input || input.length === 0) return []
  return input.reduce((finalValue, currentNumber)=> {
    return Math.sign(currentNumber) === 1 ? [finalValue[0]+1, finalValue[1]] : [finalValue[0], currentNumber + finalValue[1]]
  }, [0,0])
}