Throttling Function, based heavily on Underscore's but updated for ES6.

throttle.js

// Returns a function, that, when invoked, will only be triggered at most once
// during a given window of time. Normally, the throttled function will run
// as much as it can, without ever going more than once per `wait` duration;
// but if you'd like to disable the execution on the leading edge, pass
// `{leading: false}`. To disable execution on the trailing edge, ditto.

const throttle = function(func, wait, options) {
  let timeout, context, args, result;
  let previous = 0;

  /** There is nothing wrong with doing this **/
  /* eslint-disable no-param-reassign*/

  if (!options) {
    options = {};
  }

  /* eslint-enable no-param-reassign*/


  const later = function() {
    if (options.leading === false) {
      previous = 0;
    } else {
      previous = new Date().getTime();
    }

    timeout = null;
    result = Reflect.apply(func, context, args);
    if (!timeout) context = args = null;
  };

  const throttled = function(...eventArguments) {
    const now = new Date().getTime();

    args = eventArguments;

    if (!previous && options.leading === false) previous = now;
    const remaining = wait - (now - previous);

    if (remaining <= 0 || remaining > wait) {
      if (timeout) {
        clearTimeout(timeout);
        timeout = null;
      }
      previous = now;
      result = Reflect.apply(func, this, args);
      if (!timeout) context = args = null;
    } else if (!timeout && options.trailing !== false) {
      timeout = setTimeout(later, remaining);
    }
    return result;
  };

  throttled.cancel = function() {
    clearTimeout(timeout);
    previous = 0;
    timeout = context = args = null;
  };

  return throttled;
};

module.exports = throttle;