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: / usr / share / grafana / public / app / features / alerting / unified / hooks /

Filename : usePagination.ts

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import { chunk, clamp } from 'lodash';
import { useCallback, useEffect, useState, useMemo } from 'react';

export function usePagination<T>(items: T[], initialPage = 1, itemsPerPage: number) {
  const [page, setPage] = useState(initialPage);

  const pages = useMemo(() => chunk(items, itemsPerPage), [items, itemsPerPage]);

  const numberOfPages = pages.length;
  const pageItems = pages[page - 1] ?? [];

  const pageStart = (page - 1) * itemsPerPage + 1;
  const pageEnd = clamp(page * itemsPerPage, items.length);

  const onPageChange = useCallback(
    (newPage: number) => {
      setPage(clamp(newPage, 1, pages.length));
    },
    [setPage, pages]
  );

  const nextPage = useCallback(() => onPageChange(page + 1), [page, onPageChange]);
  const previousPage = useCallback(() => onPageChange(page - 1), [page, onPageChange]);

  // Reset the current page when number of pages has been changed
  useEffect(() => setPage(1), [numberOfPages]);

  return { page, onPageChange, numberOfPages, pageItems, pageStart, pageEnd, nextPage, previousPage };
}