Implement react-intersection-observer to facilitate infinite scroll

Uses react-intersection-observer to load more comments when the last of the previously loaded comments is in the viewport.
2026-02-16 10:42:08 +00:00 · 2023-04-09 18:41:58 -04:00
parent 8981bcb4b8
commit 915adb722a
12 changed files with 157 additions and 109 deletions
--- a/components/BeerById/BeerCommentForm.tsx
+++ b/components/BeerById/BeerCommentForm.tsx
@@ -8,7 +8,6 @@ import { Rating } from 'react-daisyui';
 import { useForm, SubmitHandler } from 'react-hook-form';
 import { z } from 'zod';

-
 import { useRouter } from 'next/router';
 import useBeerPostComments from '@/hooks/useBeerPostComments';
 import Button from '../ui/forms/Button';
@@ -18,10 +17,9 @@ import FormLabel from '../ui/forms/FormLabel';
 import FormSegment from '../ui/forms/FormSegment';
 import FormTextArea from '../ui/forms/FormTextArea';

-
 interface BeerCommentFormProps {
  beerPost: z.infer<typeof beerPostQueryResult>;
-  mutate: ReturnType<typeof useBeerPostComments>['mutate']
+  mutate: ReturnType<typeof useBeerPostComments>['mutate'];
 }

 const BeerCommentForm: FunctionComponent<BeerCommentFormProps> = ({
@@ -43,7 +41,6 @@ const BeerCommentForm: FunctionComponent<BeerCommentFormProps> = ({
    reset({ rating: 0, content: '' });
  }, [reset]);

-  const router = useRouter();
  const onSubmit: SubmitHandler<z.infer<typeof BeerCommentValidationSchema>> = async (
    data,
  ) => {
@@ -54,14 +51,8 @@ const BeerCommentForm: FunctionComponent<BeerCommentFormProps> = ({
      rating: data.rating,
      beerPostId: beerPost.id,
    });
+    await mutate();
    reset();
-
-    const submitTasks: Promise<unknown>[] = [
-      router.push(`/beers/${beerPost.id}`, undefined, { scroll: false }),
-      mutate(),
-    ];
-
-    await Promise.all(submitTasks);
  };

  const { errors } = formState;
--- a/components/BeerById/BeerPostCommentsSection.tsx
+++ b/components/BeerById/BeerPostCommentsSection.tsx
@@ -3,20 +3,35 @@ import UserContext from '@/contexts/userContext';

 import beerPostQueryResult from '@/services/BeerPost/schema/BeerPostQueryResult';

-import { FC, useContext } from 'react';
+import { FC, MutableRefObject, useContext, useRef } from 'react';
 import { z } from 'zod';
 import useBeerPostComments from '@/hooks/useBeerPostComments';
 import { useRouter } from 'next/router';
+import { useInView } from 'react-intersection-observer';
 import BeerCommentForm from './BeerCommentForm';

 import CommentCardBody from './CommentCardBody';
 import NoCommentsCard from './NoCommentsCard';
 import CommentLoadingCardBody from './CommentLoadingCardBody';
+import Spinner from '../ui/Spinner';

 interface BeerPostCommentsSectionProps {
  beerPost: z.infer<typeof beerPostQueryResult>;
 }

+const LoadingComponent: FC<{ length: number }> = ({ length }) => {
+  return (
+    <>
+      {Array.from({ length }).map((_, i) => (
+        <CommentLoadingCardBody key={i} />
+      ))}
+      <div className="p-1">
+        <Spinner size="sm" />
+      </div>
+    </>
+  );
+};
+
 const BeerPostCommentsSection: FC<BeerPostCommentsSectionProps> = ({ beerPost }) => {
  const { user } = useContext(UserContext);
  const router = useRouter();
@@ -24,13 +39,22 @@ const BeerPostCommentsSection: FC<BeerPostCommentsSectionProps> = ({ beerPost })
  const pageNum = parseInt(router.query.comments_page as string, 10) || 1;
  const PAGE_SIZE = 6;

-  const { comments, isLoading, mutate, setSize, size, isLoadingMore } =
+  const { comments, isLoading, mutate, setSize, size, isLoadingMore, isAtEnd } =
    useBeerPostComments({
      id,
      pageNum,
      pageSize: PAGE_SIZE,
    });

+  const { ref } = useInView({
+    delay: 3000,
+    onChange: (visible) => {
+      if (!visible || isAtEnd) return;
+      setSize(size + 1);
+    },
+  });
+
+  const sectionRef: MutableRefObject<HTMLDivElement | null> = useRef(null);
  return (
    <div className="w-full space-y-3 md:w-[60%]">
      <div className="card h-96 bg-base-300">
@@ -46,29 +70,44 @@ const BeerPostCommentsSection: FC<BeerPostCommentsSectionProps> = ({ beerPost })
      </div>

      {comments && !!comments.length && !isLoading && (
-        <div className="card bg-base-300 pb-6">
-          {comments.map((comment) => (
-            <CommentCardBody key={comment.id} comment={comment} mutate={mutate} />
-          ))}
+        <div className="card bg-base-300 pb-6" ref={sectionRef}>
+          {comments.map((comment, index) => {
+            const isLastComment = index === comments.length - 1;

-          {isLoadingMore &&
-            Array.from({ length: PAGE_SIZE }).map((_, i) => (
-              <CommentLoadingCardBody key={i} />
-            ))}
+            return (
+              <div ref={isLastComment ? ref : undefined} key={comment.id}>
+                <CommentCardBody comment={comment} mutate={mutate} />
+              </div>
+            );
+          })}

-          <button type="button" onClick={() => setSize(size + 1)}>
-            load more
+          {!!isLoadingMore && (
+            <div>
+              <LoadingComponent length={Math.floor(PAGE_SIZE / 2)} />
+            </div>
+          )}
+
+          {isAtEnd && (
+            <div className="flex h-10 items-center justify-center text-center">
+              <button
+                className="btn-ghost btn-sm btn"
+                type="button"
+                onClick={() => {
+                  sectionRef.current!.scrollIntoView({ behavior: 'smooth' });
+                }}
+              >
+                Scroll to top of comments
              </button>
            </div>
          )}
+        </div>
+      )}

      {!comments?.length && !isLoading && <NoCommentsCard />}

      {isLoading && (
        <div className="card bg-base-300 pb-6">
-          {Array.from({ length: PAGE_SIZE }).map((_, i) => (
-            <CommentLoadingCardBody key={i} />
-          ))}
+          <LoadingComponent length={PAGE_SIZE} />
        </div>
      )}
    </div>
--- a/components/BeerById/BeerPostLikeButton.tsx
+++ b/components/BeerById/BeerPostLikeButton.tsx
@@ -3,7 +3,6 @@ import sendLikeRequest from '@/requests/sendLikeRequest';
 import { FC, useEffect, useState } from 'react';
 import { FaThumbsUp, FaRegThumbsUp } from 'react-icons/fa';

-
 import useGetLikeCount from '@/hooks/useGetLikeCount';

 const BeerPostLikeButton: FC<{
@@ -32,7 +31,8 @@ const BeerPostLikeButton: FC<{
  return (
    <button
      type="button"
-      className={`btn gap-2 rounded-2xl ${!isLiked ? 'btn-ghost outline' : 'btn-primary'
+      className={`btn gap-2 rounded-2xl ${
+        !isLiked ? 'btn-ghost outline' : 'btn-primary'
      }`}
      onClick={() => {
        handleLike();
--- a/components/BeerById/CommentCardBody.tsx
+++ b/components/BeerById/CommentCardBody.tsx
@@ -8,11 +8,13 @@ import { FC, useContext } from 'react';
 import { Rating } from 'react-daisyui';

 import { FaEllipsisH } from 'react-icons/fa';
+import { useInView } from 'react-intersection-observer';
 import { z } from 'zod';

 interface CommentCardProps {
  comment: z.infer<typeof BeerCommentQueryResult>;
  mutate: ReturnType<typeof useBeerPostComments>['mutate'];
+  ref?: ReturnType<typeof useInView>['ref'];
 }

 const CommentCardDropdown: FC<CommentCardProps> = ({ comment, mutate }) => {
@@ -42,16 +44,10 @@ const CommentCardDropdown: FC<CommentCardProps> = ({ comment, mutate }) => {
        className="dropdown-content menu rounded-box w-52 bg-base-100 p-2 shadow"
      >
        <li>
-
-
          {isCommentOwner ? (
-
            <button onClick={handleDelete}>Delete</button>
-
          ) : (
-
            <button>Report</button>
-
          )}
        </li>
      </ul>
@@ -59,14 +55,13 @@ const CommentCardDropdown: FC<CommentCardProps> = ({ comment, mutate }) => {
  );
 };

-const CommentCardBody: FC<CommentCardProps>
-  = ({ comment, mutate }) => {
+const CommentCardBody: FC<CommentCardProps> = ({ comment, mutate, ref }) => {
  const { user } = useContext(UserContext);

  const timeDistance = useTimeDistance(new Date(comment.createdAt));

  return (
-      <div className="card-body animate-in fade-in-10">
+    <div className="card-body animate-in fade-in-10" ref={ref}>
      <div className="flex flex-col justify-between sm:flex-row">
        <div>
          <h3 className="font-semibold sm:text-2xl">
@@ -105,6 +100,6 @@ const CommentCardBody: FC<CommentCardProps>
      </div>
    </div>
  );
-  };
+};

 export default CommentCardBody;
--- a/components/BeerById/CommentLoadingCardBody.tsx
+++ b/components/BeerById/CommentLoadingCardBody.tsx
@@ -1,12 +1,14 @@
 const CommentLoadingCardBody = () => {
  return (
-    <div className="animate card-body h-64 fade-in-10">
+    <div className="animate card-body h-52 fade-in-10">
      <div className="flex animate-pulse space-x-4 slide-in-from-top">
        <div className="flex-1 space-y-4 py-1">
          <div className="h-4 w-3/4 rounded bg-base-100" />
          <div className="space-y-2">
            <div className="h-4 rounded bg-base-100" />
-            <div className="h-4 w-5/6 rounded bg-base-100" />
+            <div className="h-4 w-11/12 rounded bg-base-100" />
+            <div className="h-4 w-10/12 rounded bg-base-100" />
+            <div className="h-4 w-11/12 rounded bg-base-100" />
          </div>
        </div>
      </div>
--- a/components/ui/Spinner.tsx
+++ b/components/ui/Spinner.tsx
@@ -6,8 +6,8 @@ interface SpinnerProps {

 const Spinner: FC<SpinnerProps> = ({ size = 'md' }) => {
  const spinnerWidths: Record<NonNullable<SpinnerProps['size']>, `w-[${number}px]`> = {
-    xs: 'w-[10px]',
-    sm: 'w-[20px]',
+    xs: 'w-[45px]',
+    sm: 'w-[60px]',
    md: 'w-[100px]',
    lg: 'w-[150px]',
    xl: 'w-[200px]',
--- a/contexts/userContext.ts
+++ b/contexts/userContext.ts
@@ -7,7 +7,7 @@ const UserContext = createContext<{
  user?: z.infer<typeof GetUserSchema>;
  error?: unknown;
  isLoading: boolean;
-  mutate?: ReturnType<typeof useUser>['mutate']
+  mutate?: ReturnType<typeof useUser>['mutate'];
 }>({ isLoading: true });

 export default UserContext;
--- a/hooks/useBeerPostComments.ts
+++ b/hooks/useBeerPostComments.ts
@@ -21,9 +21,7 @@ interface UseBeerPostCommentsProps {
 *   the data.
 */
 const useBeerPostComments = ({ id, pageSize }: UseBeerPostCommentsProps) => {
-  const { data, error, isLoading, mutate, size, setSize } = useSWRInfinite(
-    (index) => `/api/beers/${id}/comments?page_num=${index + 1}&page_size=${pageSize}`,
-    async (url) => {
+  const fetcher = async (url: string) => {
    const response = await fetch(url);
    const json = await response.json();
    const count = response.headers.get('X-Total-Count');
@@ -32,10 +30,7 @@ const useBeerPostComments = ({ id, pageSize }: UseBeerPostCommentsProps) => {
    if (!parsed.success) {
      throw new Error(parsed.error.message);
    }
-      const parsedPayload = z
-
-        .array(BeerCommentQueryResult)
-        .safeParse(parsed.data.payload);
+    const parsedPayload = z.array(BeerCommentQueryResult).safeParse(parsed.data.payload);

    if (!parsedPayload.success) {
      throw new Error(parsedPayload.error.message);
@@ -43,14 +38,22 @@ const useBeerPostComments = ({ id, pageSize }: UseBeerPostCommentsProps) => {

    const pageCount = Math.ceil(parseInt(count as string, 10) / pageSize);
    return { comments: parsedPayload.data, pageCount };
-    },
+  };
+
+  const { data, error, isLoading, mutate, size, setSize } = useSWRInfinite(
+    (index) => `/api/beers/${id}/comments?page_num=${index + 1}&page_size=${pageSize}`,
+    fetcher,
+    { parallel: true },
  );

  const comments = data?.flatMap((d) => d.comments) ?? [];
+  const pageCount = data?.[0].pageCount ?? 0;

  const isLoadingMore =
    isLoading || (size > 0 && data && typeof data[size - 1] === 'undefined');

+  const isAtEnd = !(size < data?.[0].pageCount!);
+
  return {
    comments,
    isLoading,
@@ -59,6 +62,8 @@ const useBeerPostComments = ({ id, pageSize }: UseBeerPostCommentsProps) => {
    size,
    setSize,
    isLoadingMore,
+    isAtEnd,
+    pageCount,
  };
 };

--- a/package-lock.json
+++ b/package-lock.json
@@ -35,6 +35,7 @@
        "react-email": "^1.9.0",
        "react-hook-form": "^7.43.9",
        "react-icons": "^4.8.0",
+        "react-intersection-observer": "^9.4.3",
        "sparkpost": "^2.1.4",
        "swr": "^2.1.2",
        "zod": "^3.21.4"
@@ -8341,6 +8342,14 @@
        "react": "*"
      }
    },
+    "node_modules/react-intersection-observer": {
+      "version": "9.4.3",
+      "resolved": "https://registry.npmjs.org/react-intersection-observer/-/react-intersection-observer-9.4.3.tgz",
+      "integrity": "sha512-WNRqMQvKpupr6MzecAQI0Pj0+JQong307knLP4g/nBex7kYfIaZsPpXaIhKHR+oV8z+goUbH9e10j6lGRnTzlQ==",
+      "peerDependencies": {
+        "react": "^15.0.0 || ^16.0.0 || ^17.0.0 || ^18.0.0"
+      }
+    },
    "node_modules/react-is": {
      "version": "16.13.1",
      "resolved": "https://registry.npmjs.org/react-is/-/react-is-16.13.1.tgz",
@@ -15901,6 +15910,12 @@
      "integrity": "sha512-N6+kOLcihDiAnj5Czu637waJqSnwlMNROzVZMhfX68V/9bu9qHaMIJC4UdozWoOk57gahFCNHwVvWzm0MTzRjg==",
      "requires": {}
    },
+    "react-intersection-observer": {
+      "version": "9.4.3",
+      "resolved": "https://registry.npmjs.org/react-intersection-observer/-/react-intersection-observer-9.4.3.tgz",
+      "integrity": "sha512-WNRqMQvKpupr6MzecAQI0Pj0+JQong307knLP4g/nBex7kYfIaZsPpXaIhKHR+oV8z+goUbH9e10j6lGRnTzlQ==",
+      "requires": {}
+    },
    "react-is": {
      "version": "16.13.1",
      "resolved": "https://registry.npmjs.org/react-is/-/react-is-16.13.1.tgz",
--- a/package.json
+++ b/package.json
@@ -38,6 +38,7 @@
    "react-email": "^1.9.0",
    "react-hook-form": "^7.43.9",
    "react-icons": "^4.8.0",
+    "react-intersection-observer": "^9.4.3",
    "sparkpost": "^2.1.4",
    "swr": "^2.1.2",
    "zod": "^3.21.4"
--- a/prisma/seed/create/createNewUsers.ts
+++ b/prisma/seed/create/createNewUsers.ts
@@ -18,7 +18,7 @@ const createNewUsers = async ({ numberOfUsers }: CreateNewUsersArgs) => {

  // eslint-disable-next-line no-plusplus
  for (let i = 0; i < numberOfUsers; i++) {
-    const randomValue = crypto.randomBytes(4).toString('hex');
+    const randomValue = crypto.randomBytes(8).toString('hex');
    const firstName = faker.name.firstName();
    const lastName = faker.name.lastName();
    const username = `${firstName[0]}.${lastName}.${randomValue}`;
--- a/prisma/seed/index.ts
+++ b/prisma/seed/index.ts
@@ -29,7 +29,7 @@ import createNewUsers from './create/createNewUsers';
      createNewBeerTypes({ joinData: { users } }),
    ]);
    const beerPosts = await createNewBeerPosts({
-      numberOfPosts: 48,
+      numberOfPosts: 200,
      joinData: { breweryPosts, beerTypes, users },
    });

@@ -41,11 +41,11 @@ import createNewUsers from './create/createNewUsers';
      breweryImages,
    ] = await Promise.all([
      createNewBeerPostComments({
-        numberOfComments: 1000,
+        numberOfComments: 45000,
        joinData: { beerPosts, users },
      }),
      createNewBreweryPostComments({
-        numberOfComments: 1000,
+        numberOfComments: 45000,
        joinData: { breweryPosts, users },
      }),
      createNewBeerPostLikes({