get-multiplier.js

var mlcm = require('mlcm')
  , frac = require('frac')

module.exports = function  getMultiplier (prizes) {
  if (prizes.length === 0) return 0
  if (Array.isArray(prizes) === false) throw new Error('getMultiplier requires an array')

  return mlcm(prizes.map(function (prize) {
    return frac(prize.chance, Infinity)[2]
  }))
}