How to add `onscroll` event in ReactJS component

App.js

import React from 'react';

let lastScrollY = 0;
let ticking = false;

class App extends React.Component {
  componentDidMount() {
    window.addEventListener('scroll', this.handleScroll, true);
  }

  componentWillUnmount() {
    window.removeEventListener('scroll', this.handleScroll);
  }
    
  nav = React.createRef();
  
  handleScroll = () => {
    lastScrollY = window.scrollY;

    if (!ticking) {
      window.requestAnimationFrame(() => {
        this.nav.current.style.top = `${lastScrollY}px`;
        ticking = false;
      });
   
      ticking = true;
    }
  };

  render() {
    return (
      <div>
        <nav ref={this.nav}>
        </nav>
      <div>
    );
  }
}

export default App;

Hi @j6k4m8 , this.handleScroll = this.handleScroll.bind(this); Work very well with the traditionnal method declaration Syntax

constructor(props) {
  super(props);
  this.handleScroll = this.handleScroll.bind(this);
}
handleScroll(event) {
  console.log('the scroll things', event)
};

In case you're interested by making you're constructor more dry you could also use the ES6 fat arrow syntax.

constructor(props) {
  super(props);
}
handleScroll = (event) =>  {
  console.log('the scroll things', event)
};

Fat arrow automatically bind this to the method, allowing shorter constructor. Especially when you have a lot of methods.

@jylopez, worked for me too, thanks!

@jylopez worked perfectly for me. thank you so much!

@ffxsam your solution works for me ~thank you a lot

componentDidMount() {
    // $FlowFixMe
    const node = this.hscroll;
    if (node) {
      node.addEventListener('scroll', e => {
        window.requestAnimationFrame(() => {
          this.setState({ fixed: node.scrollTop > 10 });
        });
      });
    }
  }

componentWillUnmount() {
    // $FlowFixMe
    this.hscroll.removeEventListener('scroll');
  }

render() {
    return (
      // $FlowFixMe
      <Container innerRef={comp => (this.hscroll = comp)}>

this is my solution :

componentDidMount = () => {
   // hadling cover parallax 
    window.addEventListener('scroll', this.handleOnScroll)
}

componentWillUnmount = () => {
    window.removeEventListener('scroll', this.handleOnScroll)
}

// handle onScroll event
handleOnScroll = () => {
    // console.log(this.coverRef.current.height)
    const wScroll = window.scrollY
    this.coverGradRef.current.style.cssText = `transform: translate(0px , -${wScroll/40}%)`
    // console.log(window.scrollY)
}

coverGradRef is a ref that is in my component's constructor and i pass that to child component, it works pretty smooth so far

and one more thing
after this.coverGradRef.current.style you can add cssText and add what every property you want like pure css , if you don't like that you can use something like this.coverGradRef.current.style.top = '10px' and instead of top you can put any valid css property

componentDidMount(){
document.addEventListener('scroll', this.handleScroll, true);
}
handleScroll = () => {
console.log('scrolling ...');
}

Note however that input events and animation frames are fired at about the same rate and therefore the optimization below is often unnecessary.

https://developer.mozilla.org/en-US/docs/Web/Events/scroll#Example

Hi @jylopez This is what I needed. Thanks! Appreciated the ES6 tip from @EEtancelin. I like not having to add the bindings in the constructor. Good stuff!

Good stuff @jylopez. Has anyone had any issue with the scroll event not firing on mobile. The touchmove event is what native js uses and I see react has onTouchMove but that is react native specific.

@jylopez Thank you so much.. it is working fine

@ffxsam solution worked fine for me too.

@jylopez @EEtancelin best solutions, thx!

solved my problem thanks

If anyone is thinking they are going crazy that it's not working for them, while everyone else is piling on saying it does, try this:

  componentDidMount() {
    window.addEventListener('scroll', this.handleScroll, true);
  }

Note, the third argument of "true".

https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener

@paintedbicycle thank you! now it works.

If anyone is thinking they are going crazy that it's not working for them, while everyone else is piling on saying it does, try this:

  componentDidMount() {
    window.addEventListener('scroll', this.handleScroll, true);
  }

Note, the third argument of "true".

https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener

Worked for me!

window.addEventListener('scroll', this.handleScroll, true);

Thanks!

@paintedbicycle Thank you!! This worked for me

Thanks this is exactly what I needed to do for a ShadowDOM supported div that used onScroll.
Turns out ShadowDOM does not support scroll listener, it's essentially blocked.

What I did was:

const listNode = ReactDOM.findDOMNode(this.list);
listNode.addEventListener('scroll', this.handleScroll);

and it worked! 🎉

If anyone is thinking they are going crazy that it's not working for them, while everyone else is piling on saying it does, try this:

  componentDidMount() {
    window.addEventListener('scroll', this.handleScroll, true);
  }

Note, the third argument of "true".

https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener

Worked for me

thank you very much @paintedbicycle

This worked for me:

constructor(props) {
  super(props);
  this.handleScroll = this.handleScroll.bind(this);
}

componentDidMount() {
  window.addEventListener('scroll', this.handleScroll);
};

componentWillUnmount() {
  window.removeEventListener('scroll', this.handleScroll);
};

handleScroll(event) {
  console.log('the scroll things', event)
};

your solution worked for me. Thank you for this

@raheemazeezabiodun Note, that if you use an arrow function syntax for declaring custom handlers, you won't need to bind them to this inside of a constructor function:

constructor(props) {
  supert(props);
  this.handleScroll = this.handleScroll.bind(this);
}

handleScroll(event) { ... };

vs

handleScroll = (event) => { ... };

Is anyone having issues with the event returning as undefined?