refactor(app): move react components to react codebase [EE-3179] (#6971)

app/react/components/PaginationControls/calculatePageNumber.ts

@@ -0,0 +1,37 @@
+/**
+ * Given the position in the sequence of pagination links, figure out what page number corresponds to that position.
+ *
+ * @param position
+ * @param currentPage
+ * @param paginationRange
+ * @param totalPages
+ */
+export function calculatePageNumber(
+  position: number,
+  currentPage: number,
+  paginationRange: number,
+  totalPages: number
+) {
+  const halfWay = Math.ceil(paginationRange / 2);
+  if (position === paginationRange) {
+    return totalPages;
+  }
+
+  if (position === 1) {
+    return position;
+  }
+
+  if (paginationRange < totalPages) {
+    if (totalPages - halfWay < currentPage) {
+      return totalPages - paginationRange + position;
+    }
+
+    if (halfWay < currentPage) {
+      return currentPage - halfWay + position;
+    }
+
+    return position;
+  }
+
+  return position;
+}