calculatePagination method

void calculatePagination()

logic

Implementation

void calculatePagination() {
  numberNextPage = getNumberNextPage;
  excessStart = currentPage - numberNextPage <= 0 ? numberNextPage - (currentPage - 1) : 0;
  excessEnd = currentPage + numberNextPage >= pageNumber
      ? numberNextPage - (pageNumber - currentPage)
      : 0;
  startPage = currentPage - numberNextPage <= 0 ? 1 : currentPage - numberNextPage - excessStart;
  endPage = currentPage + numberNextPage >= pageNumber
      ? pageNumber
      : currentPage + numberNextPage + excessEnd;
}