Detecting when user scrolls to bottom of div with React js

Question

An even simpler way to do it is with scrollHeight, scrollTop, and clientHeight.

Subtract the scrolled height from the total scrollable height. If this is equal to the visible area, you've reached the bottom!

element.scrollHeight - element.scrollTop === element.clientHeight

In react, just add an onScroll listener to the scrollable element, and use event.target in the callback.

class Scrollable extends Component {

  handleScroll = (e) => {
    const bottom = e.target.scrollHeight - e.target.scrollTop === e.target.clientHeight;
    if (bottom) { ... }
  }

  render() {
    return (
      <ScrollableElement onScroll={this.handleScroll}>
        <OverflowingContent />
      </ScrollableElement>
    );
  }
}

I found this to be more intuitive because it deals with the scrollable element itself, not the window, and it follows the normal React way of doing things (not using ids, ignoring DOM nodes).

You can also manipulate the equation to trigger higher up the page (lazy loading content/infinite scroll, for example).

you can use el.getBoundingClientRect().bottom to check if the bottom has been viewed

isBottom(el) {
  return el.getBoundingClientRect().bottom <= window.innerHeight;
}

componentDidMount() {
  document.addEventListener('scroll', this.trackScrolling);
}

componentWillUnmount() {
  document.removeEventListener('scroll', this.trackScrolling);
}

trackScrolling = () => {
  const wrappedElement = document.getElementById('header');
  if (this.isBottom(wrappedElement)) {
    console.log('header bottom reached');
    document.removeEventListener('scroll', this.trackScrolling);
  }
};

Here's a solution using React Hooks and ES6:

import React, { useRef, useEffect } from 'react';

const MyListComponent = () => {
  const listInnerRef = useRef();

  const onScroll = () => {
    if (listInnerRef.current) {
      const { scrollTop, scrollHeight, clientHeight } = listInnerRef.current;
      if (scrollTop + clientHeight === scrollHeight) {
        // TO SOMETHING HERE
        console.log('Reached bottom')
      }
    }
  };

  return (
    <div className="list">
      <div className="list-inner" onScroll={() => onScroll()} ref={listInnerRef}>
        {/* List items */}
      </div>
    </div>
  );
};

export default List;

We can also detect div's scroll end by using ref.

import React, { Component } from 'react';
import {withRouter} from 'react-router-dom';
import styles from 'style.scss';

class Gallery extends Component{ 

  paneDidMount = (node) => {    
    if(node) {      
      node.addEventListener("scroll", this.handleScroll.bind(this));      
    }
  }

  handleScroll = (event) => {    
    var node = event.target;
    const bottom = node.scrollHeight - node.scrollTop === node.clientHeight;
    if (bottom) {      
      console.log("BOTTOM REACHED:",bottom); 
    }    
  }

  render() {
    var that = this;        
    return(<div className={styles.gallery}>
      <div ref={that.paneDidMount} className={styles.galleryContainer}>
        ...
      </div>

    </div>);   
  }
}

export default withRouter(Gallery);

This answer belongs to Brendan, let's make it functional

export default () => {
   const handleScroll = (e) => {
       const bottom = e.target.scrollHeight - e.target.scrollTop === e.target.clientHeight;
       if (bottom) { 
           console.log("bottom")
       }
    }

  return (
     <div onScroll={handleScroll}  style={{overflowY: 'scroll', maxHeight: '400px'}}  >
        //overflowing elements here
   </div>
  )
}

If the first div is not scrollable it won't work and onScroll didn't work for me in a child element like div after the first div so onScroll should be at the first HTML tag that has an overflow

Extending chandresh's answer to use react hooks and ref I would do it like this;

import React, {useState, useEffect} from 'react';

export default function Scrollable() {
    const [referenceNode, setReferenceNode] = useState();
    const [listItems] = useState(Array.from(Array(30).keys(), (n) => n + 1));

    useEffect(() => {
        return () => referenceNode.removeEventListener('scroll', handleScroll);
    }, []);

    function handleScroll(event) {
        var node = event.target;
        const bottom = node.scrollHeight - node.scrollTop === node.clientHeight;
        if (bottom) {
            console.log('BOTTOM REACHED:', bottom);
        }
    }

    const paneDidMount = (node) => {
        if (node) {
            node.addEventListener('scroll', handleScroll);
            setReferenceNode(node);
        }
    };

    return (
        <div
            ref={paneDidMount}
            style={{overflowY: 'scroll', maxHeight: '400px'}}
        >
            <ul>
                {listItems.map((listItem) => <li>List Item {listItem}</li>)}
            </ul>
        </div>
    );
}

Add following functions in your React.Component and you're done :]

  componentDidMount() {
    window.addEventListener("scroll", this.onScroll, false);
  }

  componentWillUnmount() {
    window.removeEventListener("scroll", this.onScroll, false);
  }

  onScroll = () => {
    if (this.hasReachedBottom()) {
      this.props.onScrollToBottom();
    }
  };

  hasReachedBottom() {
    return (
      document.body.offsetHeight + document.body.scrollTop ===
      document.body.scrollHeight
    );
  }