calculate LCM using javascript reduce and recursive GCD calculator

LCM

function smallestCommons(arr) {
  range = findRange(arr);
  return calcRangeLCM(range);
}
function findRange(arr){
  //arr=[1,5] ==> res=[1,2,3,4,5]
  var res = [];
  var min = Math.min.apply(null,arr);
  var max = Math.max.apply(null,arr);
  for(var i = min; i <=max;i++){
    res.push(i);
  }
  return res;
}
function calcRangeLCM(range){
  return range.reduce(function(c,l){
            return calcLCM(c,l);
          },1);

}
function calcLCM(a,b){
  return a * b / calcGCD(a,b);
}
function calcGCD(a,b){
  if ( ! b) {
        return a;
  }
  return calcGCD(b, a % b);
}

smallestCommons([1,5]);