code: function isDirectionRTL(
    str: string,
    strongFallback: ?BidiDirection,
  ): boolean {
    return getDirection(str, strongFallback) === UnicodeBidiDirection.RTL;
  }
docs: Returns true if getDirection(arguments...) returns RTL.
  
  @param str             A text block; e.g. paragraph, table cell
  @param strongFallback  Fallback direction, used if no strong direction
  detected for the block (default = global direction)
  @return                True if the resolved direction is RTL