http://www.freecodecamp.com/narshe1412 's solution for Bonfire:Smallest Common Multiple

Smallest Common Multiple.js

function smallestCommons(arr) {
  // Greates common divisor formula
  function gcd(a, b) {
    while (b !== 0) {
       var t = b; 
       b = a % b; 
       a = t; 
      }
    return a; 
  }
  // Least common multiple formula (based on GCD)
  function lcm(a,b) {
    return a*b/gcd(a,b);
  }
  
  // We determine what's the highest value passed
  var max, min;
  /* ---- OLD CODE -----
  if (arr[0] > arr[1]) {
    max = arr[0];
    min = arr[1];
  } else {
    max = arr[1];
    min = arr[0];
  } */
  max = Math.max(...arr); //<<- this code only available in ES6
  min = Math.min(...arr);
  
  // We navigate the numbers, always calculating the LCM from the previous result to the next number
  // Previous result will always be the LCM from all the previous, per multiplication properties
  var result = min;
  for (var i=min; i<= max; i++){
    result = lcm(result,i);
  }
  
  return result;
}