ScrollToTopButton Component

This component adds a fixed floating Back to Top button. It becomes visible after the user scrolls 300px vertically; on click it triggers a smooth scroll to the top while playing a short visual animation on the icon. It does not expose public props: customization (threshold, image) is done by editing the source (index.js). The goal is to keep it lightweight and easy to reuse.

Overview

Implemented features:

• Appears after 300px scroll (hard‑coded condition)
• Smooth scroll to top on click
• CSS animation on click (fly + @keyframes flyUp)
• Show/Hide using opacity + visibility
• Scroll listener with cleanup in useEffect
• Icon image can be swapped by changing the import

Component Code

src/components/ScrollToTopButton/index.js

import React, { useState, useEffect } from "react";
import clsx from "clsx";
import styles from "./styles.module.css";
import buttontop from '@site/static/img/buttontop.PNG'

export default function ScrollToTopButton() {
  const [isVisible, setIsVisible] = useState(false);
  const [fly, setFly] = useState(false);

  useEffect(() => {
    const toggleVisibility = () => {
      if (window.scrollY > 300) {
        setIsVisible(true);
      } else {
        setIsVisible(false);
      }
    };
    window.addEventListener("scroll", toggleVisibility);
    return () => window.removeEventListener("scroll", toggleVisibility);
  }, []);

  const scrollToTop = () => {
    setFly(true);
    window.scrollTo({ top: 0, behavior: "smooth" });

    setTimeout(() => setFly(false), 800);
  };

  return (
    <div
      className={clsx(
        styles.scrollBtn,
        isVisible && styles.show,
        fly && styles.fly
      )}
      onClick={scrollToTop}
    >
      <img
        src={buttontop}
        alt="Retour en haut"
        width="30"
        height="30"
      />
    </div>
  );
}

src/components/ScrollToTopButton/styles.module.css

.scrollBtn {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 60px;
  height: 60px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.4s, visibility 0.4s;
  z-index: 1000;
}

.scrollBtn img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
  transition: transform 0.3s;
}

.scrollBtn:hover img {
  transform: scale(1.1);
}

/* Bouton visible après scroll */
.scrollBtn.show {
  opacity: 1;
  visibility: visible;
}

/* Animation "vol vers le haut" */
.scrollBtn.fly img {
  animation: flyUp 0.8s ease-in forwards;
}

@keyframes flyUp {
  0% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
  100% {
    transform: translateY(-300px) scale(0.6);
    opacity: 0;
  }
}

Installation

1. Copy the ScrollToTopButton folder into src/components/
2. Import the component in your global layout (or a specific page)
3. Ensure the image import works (/static/img/buttontop.PNG)
4. (Optional) Replace the image with your own

File structure

src/components/ScrollToTopButton/
├── index.js              # Main React component
└── styles.module.css     # Scoped CSS Module

Configuration

• Threshold: edit if (window.scrollY > 300) in index.js
• Image: replace the imported buttontop image

Customization

Change the image

1. Place your image inside static/img/
2. Update the import in index.js:

import buttontop from '@site/static/img/your-image.png'

3. The component uses it like:

<img
  src={buttontop}
  alt="Back to top"
  width="30"
  height="30"
/>

Edit styles

Open styles.module.css and adjust:

• Position: tweak bottom / right
• Size: adjust width / height
• Visual: modify box-shadow
• Animation: change flyUp keyframes

State & Behavior

• isVisible: true when window.scrollY > 300, else false
• fly: toggled to true on click, reset after 800ms
• Scroll listener: handles visibility logic and is cleaned up on unmount

Animations

Show/Hide

transition: opacity 0.4s, visibility 0.4s;

Click animation (flyUp)

@keyframes flyUp {
  0% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
  100% {
    transform: translateY(-300px) scale(0.6);
    opacity: 0;
  }
}

Full example

import React from 'react';
import Layout from '@theme-original/Layout';
import ScrollToTopButton from '@site/src/components/ScrollToTopButton';

export default function LayoutWrapper(props) {
  return (
    <>
      <Layout {...props} />
      <ScrollToTopButton />
    </>
  );
}