Add back to top component

Remove event after unmount

components/RUA/Button.tsx

@@ -9,6 +9,8 @@ export type ButtonProps = {
 >;
 
 const Button = ({ children, ...rest }: ButtonProps) => {
+  const { className, ...props } = rest;
+
   return (
     <>
       <button
@@ -23,9 +25,10 @@ const Button = ({ children, ...rest }: ButtonProps) => {
           'disabled:hover:border-transparent',
           'text-lg disabled:bg-gray-200 disabled:text-gray-500',
           'dark:disabled:bg-gray-700 dark:disabled:text-gray-300',
-          'disabled:dark:hover:border-transparent'
+          'disabled:dark:hover:border-transparent',
+          className
         )}
-        {...rest}
+        {...props}
       >
         {children}
       </button>
@@ -33,4 +36,4 @@ const Button = ({ children, ...rest }: ButtonProps) => {
   );
 };
 
-export default Button;
+export default Button;

components/common/BackToTop.tsx

@@ -0,0 +1,29 @@
+import clsx from 'clsx';
+import Button from 'components/RUA/Button';
+import { FiChevronUp } from 'react-icons/fi';
+
+const BackToTop = () => {
+  const handleBack = () => {
+    const target = document.documentElement || document.body;
+    target.scrollTo({
+      top: 0,
+    });
+  };
+
+  return (
+    <>
+      <Button
+        onClick={handleBack}
+        className={clsx(
+          '!px-3 fixed',
+          'right-4 bottom-4',
+          'lg:right-8 lg:bottom-8'
+        )}
+      >
+        <FiChevronUp className="w-6 h-6" />
+      </Button>
+    </>
+  );
+};
+
+export default BackToTop;

layouts/MainLayout.tsx

@@ -1,20 +1,39 @@
 import dynamic from 'next/dynamic';
+import { useCallback, useEffect, useState } from 'react';
 
 const Footer = dynamic(() => import('components/Footer'));
 const HeadBar = dynamic(() => import('components/NavBar'));
+const BackToTop = dynamic(() => import('components/common/BackToTop'));
 
 type Props = {
   children: React.ReactNode;
 };
 
 const MainLayout = ({ children }: Props) => {
+  const [showTop, setShowTop] = useState(false);
+  const handleScroll = useCallback(() => {
+    const target = document.documentElement || document.body;
+    const scrollableHeight = target.scrollHeight - target.clientHeight;
+    const scrollHeight = target.scrollTop;
+    if (scrollHeight / scrollableHeight >= 0.1) {
+      setShowTop(true);
+    } else {
+      setShowTop(false);
+    }
+  }, []);
+  useEffect(() => {
+    window.addEventListener('scroll', handleScroll);
+    return () => window.removeEventListener('scroll', handleScroll);
+  }, [handleScroll]);
+
   return (
     <>
       <HeadBar />
       {children}
       <Footer />
+      {showTop && <BackToTop />}
     </>
   );
 };
 
-export default MainLayout;
+export default MainLayout;

pages/p/[slug].tsx

@@ -8,11 +8,11 @@ import { GetStaticPaths, GetStaticProps, InferGetStaticPropsType } from 'next';
 import { MDXRemote, MDXRemoteSerializeResult } from 'next-mdx-remote';
 import { serialize } from 'next-mdx-remote/serialize';
 import dynamic from 'next/dynamic';
+import { ReactElement } from 'react';
 import rehypeSlug from 'rehype-slug';
 import remarkGfm from 'remark-gfm';
 
-const Footer = dynamic(() => import('components/Footer'));
-const HeadBar = dynamic(() => import('components/NavBar'));
+const MainLayout = dynamic(() => import('layouts/MainLayout'));
 const PostComment = dynamic(() => import('components/post/PostComment'));
 
 const Slug = ({
@@ -22,8 +22,6 @@ const Slug = ({
 }: InferGetStaticPropsType<typeof getStaticProps>) => {
   return (
     <>
-      <HeadBar />
-
       <main id="article" className="relative max-w-4xl px-4 mx-auto my-10">
         <h1>{mdxSource.frontmatter?.title}</h1>
         <time>{mdxSource.frontmatter?.date}</time>
@@ -34,8 +32,6 @@ const Slug = ({
           <PostComment />
         </article>
       </main>
-
-      <Footer />
     </>
   );
 };
@@ -89,4 +85,8 @@ export const getStaticProps: GetStaticProps<{
   };
 };
 
+Slug.getLayout = function getLayout(page: ReactElement) {
+  return <MainLayout>{page}</MainLayout>;
+};
+
 export default Slug;