semantic-ui-react/src/lib/createPaginationItems/suffixFactories.js

The official Semantic-UI-React integration.

import { createEllipsisItem } from './itemFactories'

export const createInnerPrefix = (firstGroupEnd, innerGroupStart, pageFactory) => {
  const prefixPage = innerGroupStart - 1
  const showEllipsis = prefixPage !== firstGroupEnd + 1
  const prefixFactory = showEllipsis ? createEllipsisItem : pageFactory

  return prefixFactory(prefixPage)
}

export const createInnerSuffix = (innerGroupEnd, lastGroupStart, pageFactory) => {
  const suffixPage = innerGroupEnd + 1
  const showEllipsis = suffixPage !== lastGroupStart - 1
  const suffixFactory = showEllipsis ? createEllipsisItem : pageFactory

  return suffixFactory(suffixPage)
}