javascript - Load more when scrolled to bottom in Reactjs

Javascript - Load more when scrolled to bottom in Reactjs

Implementing a "load more when scrolled to the bottom" feature in React.js involves setting up an event listener to detect when the user has scrolled to the bottom of a container and triggering a function to load more data. Here's a basic example of how you can achieve this:

import React, { useState, useEffect } from 'react'; function App() { const [data, setData] = useState([]); const [loading, setLoading] = useState(false); const [page, setPage] = useState(1); const [hasMore, setHasMore] = useState(true); useEffect(() => { // Load initial data fetchData(); }, []); useEffect(() => { // Add event listener when component mounts window.addEventListener('scroll', handleScroll); return () => window.removeEventListener('scroll', handleScroll); }, []); const handleScroll = () => { if (!loading && hasMore && window.innerHeight + document.documentElement.scrollTop === document.documentElement.offsetHeight) { fetchData(); } }; const fetchData = async () => { setLoading(true); // Simulated fetch data function, replace with your actual data fetching logic const newData = await fetchMoreData(page); setPage(page + 1); setData([...data, ...newData]); setLoading(false); }; const fetchMoreData = async (page) => { // Simulated data fetching function, replace with your actual data fetching logic return new Promise(resolve => { setTimeout(() => { const newData = Array.from({ length: 10 }, (_, index) => ({ id: index + (page - 1) * 10, text: `Item ${index + (page - 1) * 10}` })); resolve(newData); }, 1000); }); }; return ( <div> <ul> {data.map(item => ( <li key={item.id}>{item.text}</li> ))} </ul> {loading && <div>Loading...</div>} {!loading && hasMore && <div>Scroll down to load more</div>} {!hasMore && <div>No more data</div>} </div> ); } export default App;

In this example:

  • We have a state variable data to store the loaded data.
  • The useEffect hook is used to load initial data when the component mounts.
  • Another useEffect hook is used to add a scroll event listener when the component mounts. The handleScroll function is called when the user scrolls.
  • Inside the handleScroll function, we check if the user has scrolled to the bottom of the page and trigger the fetchData function to load more data.
  • The fetchData function updates the data state with the newly fetched data.
  • The fetchMoreData function simulates fetching more data. You should replace it with your actual data fetching logic.
  • The component renders the loaded data and shows a loading indicator while fetching more data.
  • It also displays a message when there is no more data to load.

Make sure to replace the simulated data fetching logic in fetchMoreData with your actual data fetching logic.

Examples

  1. How to implement infinite scroll in React using JavaScript?

    • Description: This query seeks guidance on achieving infinite scrolling functionality in a React application using JavaScript.
    import React, { useState, useEffect } from 'react'; function App() { const [items, setItems] = useState([]); const [loading, setLoading] = useState(false); useEffect(() => { // Function to fetch initial data fetchData(); }, []); useEffect(() => { // Event listener for scroll window.addEventListener('scroll', handleScroll); return () => window.removeEventListener('scroll', handleScroll); }, []); const handleScroll = () => { // Check if scrolled to bottom if ( window.innerHeight + document.documentElement.scrollTop === document.documentElement.offsetHeight ) { // Load more data fetchData(); } }; const fetchData = async () => { setLoading(true); // Fetch data from API const response = await fetch('https://api.example.com/data'); const newData = await response.json(); setItems([...items, ...newData]); setLoading(false); }; return ( <div className="App"> <ul> {items.map((item, index) => ( <li key={index}>{item}</li> ))} </ul> {loading && <p>Loading...</p>} </div> ); } export default App;

  2. ReactJS load more content on scroll to bottom tutorial

    • Description: This query aims to find a tutorial explaining how to implement a load more feature in ReactJS when scrolling to the bottom of the page.
    // Implementing load more on scroll to bottom const handleScroll = () => { if ( window.innerHeight + document.documentElement.scrollTop === document.documentElement.offsetHeight ) { fetchData(); // Load more data } };

  3. ReactJS infinite scroll example code

    • Description: This query is looking for an example code snippet demonstrating how to achieve infinite scrolling in ReactJS.
    // Infinite scroll example in ReactJS useEffect(() => { window.addEventListener('scroll', handleScroll); return () => window.removeEventListener('scroll', handleScroll); }, []); const handleScroll = () => { if ( window.innerHeight + document.documentElement.scrollTop === document.documentElement.offsetHeight ) { fetchData(); // Load more data } };

  4. How to create a Load More button in ReactJS?

    • Description: This query seeks guidance on creating a "Load More" button functionality in a ReactJS application.
    // Implementing Load More button const loadMore = () => { fetchData(); // Load more data }; return ( <div> <button onClick={loadMore}>Load More</button> </div> );

  5. ReactJS scroll to load more data

    • Description: This query looks for information on how to load more data in a ReactJS application when the user scrolls to the bottom of the page.
    // Handling scroll to load more data const handleScroll = () => { if ( window.innerHeight + document.documentElement.scrollTop === document.documentElement.offsetHeight ) { fetchData(); // Load more data } };

  6. ReactJS infinite scroll pagination

    • Description: This query is interested in implementing infinite scroll pagination in a ReactJS application.
    // Infinite scroll pagination const handleScroll = () => { if ( window.innerHeight + document.documentElement.scrollTop === document.documentElement.offsetHeight ) { fetchData(); // Load more data } };

  7. ReactJS infinite scroll with useState

    • Description: This query seeks information on implementing infinite scrolling in ReactJS using the useState hook.
    // Implementing infinite scroll with useState const [items, setItems] = useState([]); const [loading, setLoading] = useState(false);

  8. How to dynamically load content on scroll in ReactJS?

    • Description: This query is interested in dynamically loading content on scroll in a ReactJS application.
    // Dynamically loading content on scroll useEffect(() => { window.addEventListener('scroll', handleScroll); return () => window.removeEventListener('scroll', handleScroll); }, []);

  9. ReactJS infinite scroll with useEffect

    • Description: This query seeks information on implementing infinite scrolling in ReactJS using the useEffect hook.
    // Implementing infinite scroll with useEffect useEffect(() => { window.addEventListener('scroll', handleScroll); return () => window.removeEventListener('scroll', handleScroll); }, []);

  10. How to achieve lazy loading in ReactJS?

    • Description: This query looks for guidance on implementing lazy loading of content in a ReactJS application.
    // Achieving lazy loading in ReactJS const fetchData = async () => { setLoading(true); // Fetch data from API const response = await fetch('https://api.example.com/data'); const newData = await response.json(); setItems([...items, ...newData]); setLoading(false); };

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