gistfile1.js

// version one... Create a clamp method.
Math.prototype.clamp = function clamp (num, min, max){
  return Math.min(min, Math.max(num, max));
}

function getDayOfWeek (day){
  return Math.clamp(day / 7, 0, 51)
}

// version two, module style
// clamp.js
module.exports = function clamp (num, min, max){
  return Math.min(min, Math.max(num, max))
}

// days.js
var clamp = require('./clamp.js')
function getDayOfWeek (day) {
   return clamp(day / 7, 0, 51)
}