refactor: move load on scroll logic to custom hook

Author: navinkarkera

src/library-authoring/LibraryCollections.tsx

@@ -1,7 +1,6 @@
-import React, { useEffect } from 'react';
 import { CardGrid } from '@openedx/paragon';
 
-import { useSearchContext } from '../search-manager';
+import { useLoadOnScroll, useSearchContext } from '../search-manager';
 import { NoComponents, NoSearchResults } from './EmptyStates';
 import CollectionCard from './components/CollectionCard';
 import { LIBRARY_SECTION_PREVIEW_LIMIT } from './components/LibrarySection';
@@ -29,26 +28,12 @@ const LibraryCollections = ({ variant }: LibraryCollectionsProps) => {
 
   const collectionList = variant === 'preview' ? collectionHits.slice(0, LIBRARY_SECTION_PREVIEW_LIMIT) : collectionHits;
 
-  useEffect(() => {
-    if (variant === 'full') {
-      const onscroll = () => {
-        // Verify the position of the scroll to implementa a infinite scroll.
-        // Used `loadLimit` to fetch next page before reach the end of the screen.
-        const loadLimit = 300;
-        const scrolledTo = window.scrollY + window.innerHeight;
-        const scrollDiff = document.body.scrollHeight - scrolledTo;
-        const isNearToBottom = scrollDiff <= loadLimit;
-        if (isNearToBottom && hasNextPage && !isFetchingNextPage) {
-          fetchNextPage();
-        }
-      };
-      window.addEventListener('scroll', onscroll);
-      return () => {
-        window.removeEventListener('scroll', onscroll);
-      };
-    }
-    return () => {};
-  }, [hasNextPage, isFetchingNextPage, fetchNextPage]);
+  useLoadOnScroll(
+    hasNextPage,
+    isFetchingNextPage,
+    fetchNextPage,
+    variant === 'full',
+  );
 
   if (totalCollectionHits === 0) {
     return isFiltered ? <NoSearchResults searchType="collection" /> : <NoComponents searchType="collection" />;

src/library-authoring/components/LibraryComponents.tsx

@@ -1,7 +1,7 @@
-import React, { useEffect, useMemo } from 'react';
+import React, { useMemo } from 'react';
 import { CardGrid } from '@openedx/paragon';
 
-import { useSearchContext } from '../../search-manager';
+import { useLoadOnScroll, useSearchContext } from '../../search-manager';
 import { NoComponents, NoSearchResults } from '../EmptyStates';
 import { useLibraryBlockTypes } from '../data/apiHooks';
 import ComponentCard from './ComponentCard';
@@ -43,26 +43,12 @@ const LibraryComponents = ({ libraryId, variant }: LibraryComponentsProps) => {
     return result;
   }, [blockTypesData]);
 
-  useEffect(() => {
-    if (variant === 'full') {
-      const onscroll = () => {
-        // Verify the position of the scroll to implementa a infinite scroll.
-        // Used `loadLimit` to fetch next page before reach the end of the screen.
-        const loadLimit = 300;
-        const scrolledTo = window.scrollY + window.innerHeight;
-        const scrollDiff = document.body.scrollHeight - scrolledTo;
-        const isNearToBottom = scrollDiff <= loadLimit;
-        if (isNearToBottom && hasNextPage && !isFetchingNextPage) {
-          fetchNextPage();
-        }
-      };
-      window.addEventListener('scroll', onscroll);
-      return () => {
-        window.removeEventListener('scroll', onscroll);
-      };
-    }
-    return () => {};
-  }, [hasNextPage, isFetchingNextPage, fetchNextPage]);
+  useLoadOnScroll(
+    hasNextPage,
+    isFetchingNextPage,
+    fetchNextPage,
+    variant === 'full',
+  );
 
   if (componentCount === 0) {
     return isFiltered ? <NoSearchResults /> : <NoComponents />;

src/search-manager/SearchManager.ts

@@ -185,3 +185,34 @@ export const useSearchContext = () => {
   }
   return ctx;
 };
+
+/**
+ * Hook which loads next page of items on scroll
+ */
+export const useLoadOnScroll = (
+  hasNextPage: boolean | undefined,
+  isFetchingNextPage: boolean,
+  fetchNextPage: () => void,
+  enabled: boolean,
+) => {
+  React.useEffect(() => {
+    if (enabled) {
+      const onscroll = () => {
+        // Verify the position of the scroll to implementa a infinite scroll.
+        // Used `loadLimit` to fetch next page before reach the end of the screen.
+        const loadLimit = 300;
+        const scrolledTo = window.scrollY + window.innerHeight;
+        const scrollDiff = document.body.scrollHeight - scrolledTo;
+        const isNearToBottom = scrollDiff <= loadLimit;
+        if (isNearToBottom && hasNextPage && !isFetchingNextPage) {
+          fetchNextPage();
+        }
+      };
+      window.addEventListener('scroll', onscroll);
+      return () => {
+        window.removeEventListener('scroll', onscroll);
+      };
+    }
+    return () => {};
+  }, [hasNextPage, isFetchingNextPage, fetchNextPage]);
+};

src/search-manager/index.ts

@@ -1,4 +1,4 @@
-export { SearchContextProvider, useSearchContext } from './SearchManager';
+export { SearchContextProvider, useLoadOnScroll, useSearchContext } from './SearchManager';
 export { default as ClearFiltersButton } from './ClearFiltersButton';
 export { default as FilterByBlockType } from './FilterByBlockType';
 export { default as FilterByTags } from './FilterByTags';