code: function binaryIndexBy(array, value, iteratee, retHighest) {
    value = iteratee(value);
  
    var low = 0,
        high = array ? array.length : 0,
        valIsNaN = value !== value,
        valIsUndef = typeof value == 'undefined';
  
    while (low < high) {
      var mid = floor((low + high) / 2),
          computed = iteratee(array[mid]),
          isReflexive = computed === computed;
  
      if (valIsNaN) {
        var setLow = isReflexive || retHighest;
      } else if (valIsUndef) {
        setLow = isReflexive && (retHighest || typeof computed != 'undefined');
      } else {
        setLow = retHighest ? (computed <= value) : (computed < value);
      }
      if (setLow) {
        low = mid + 1;
      } else {
        high = mid;
      }
    }
    return nativeMin(high, MAX_ARRAY_INDEX);
  }
docs: This function is like `binaryIndex` except that it invokes `iteratee` for
  `value` and each element of `array` to compute their sort ranking. The
  iteratee is invoked with one argument; (value).
  
  @private
  @param {Array} array The sorted array to inspect.
  @param {*} value The value to evaluate.
  @param {Function} iteratee The function invoked per iteration.
  @param {boolean} [retHighest] Specify returning the highest qualified index.
  @returns {number} Returns the index at which `value` should be inserted
  into `array`.