Dampen a value to ease it to a target value

basicEaseFunction.js

var damper = 0.5; // lower is slower

function ease(current, target) {
  current += (target - current) * damper;
  // fix Zeno's paradox: value is snapped if we're within fraction of a distance unit (usually a pixel)
  if (Math.abs(target - current) < 1) {
  	current = target;
  }
  return current;
}