function baseWhile(array, predicate, isDrop, fromRight) {
      var length = array.length,
          index = fromRight ? length : -1;

      while ((fromRight ? index-- : ++index < length) &&
        predicate(array[index], index, array)) {}

      return isDrop
        ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
        : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
    }
The base implementation of methods like `_.dropWhile` and `_.takeWhile`
without support for iteratee shorthands.

@private
@param {Array} array The array to query.
@param {Function} predicate The function invoked per iteration.
@param {boolean} [isDrop] Specify dropping elements instead of taking them.
@param {boolean} [fromRight] Specify iterating from right to left.
@returns {Array} Returns the slice of `array`.