Rename vars, code cleanup

src/utils/page-index.js

@@ -0,0 +1,25 @@
+export function getNextPageIndexLimited(currentPageIndex, pagesCount) {
+  return Math.min(currentPageIndex + 1, pagesCount - 1)
+}
+
+export function getNextPageIndexInfinte(currentPageIndex, pagesCount) {
+  const newCurrentPageIndex = currentPageIndex + 1
+  return newCurrentPageIndex > pagesCount - 1 ? 0 : newCurrentPageIndex
+}
+
+export function getNextPageIndexFn(infinite) {
+  return infinite ? getNextPageIndexInfinte : getNextPageIndexLimited
+}
+
+export function getPrevPageIndexLimited(currentPageIndex, pagesCount) {
+  return Math.max(currentPageIndex - 1, 0)
+}
+
+export function getPrevPageIndexInfinte(currentPageIndex, pagesCount) {
+  const newCurrentPageIndex = currentPageIndex - 1
+  return newCurrentPageIndex >= 0 ? newCurrentPageIndex : pagesCount - 1
+}
+
+export function getPrevPageIndexFn(infinite) {
+  return infinite ? getPrevPageIndexInfinte : getPrevPageIndexLimited
+}