Map a value in a range to another range

scale.js

/**
 * Map a value in a domain to a value in a range
 */
function scale(domainMin, domainMax, value, rangeMin, rangeMax) {
  var perc = (value - domainMin) / (domainMax - domainMin)
  return ((rangeMax - rangeMin) * perc) + rangeMin
}

scale(50, 100, 75, 100, 200)   //=> 150
scale(10, 110, 50, 200, 300)   //=> 240
scale(-50, 0, -25, -100, -200) //=> -150
scale(100, 150, 200, 10, 20)   //=> 30