Lodash Shortout

shortout.js

(function() {

  /** Used to detect hot functions by number of calls within a span of milliseconds. */
  var HOT_COUNT = 800,
      HOT_SPAN = 16;
  
  /* Built-in method references for those with the same name as other `lodash` methods. */
  var nativeNow = Date.now;
  
  /**
   * Creates a function that'll short out and invoke `identity` instead
   * of `func` when it's called `HOT_COUNT` or more times in `HOT_SPAN`
   * milliseconds.
   *
   * @private
   * @param {Function} func The function to restrict.
   * @returns {Function} Returns the new shortable function.
   */
  function shortOut(func) {
    var count = 0,
        lastCalled = 0;
  
    return function() {
      var stamp = nativeNow(),
          remaining = HOT_SPAN - (stamp - lastCalled);
  
      lastCalled = stamp;
      if (remaining > 0) {
        if (++count >= HOT_COUNT) {
          return arguments[0];
        }
      } else {
        count = 0;
      }
      return func.apply(undefined, arguments);
    };
  }

  let foo = function(defaultArg) {
    return 'foo';
  };
  
  let shortFoo = shortOut(foo);
  
  let n = shortFoo('bar');

  global.result = n;
})();