scroll to bottom of div in react-ag捕鱼王app官网

scroll to the bottom of a div in react:

1. divadd an element at the bottom of the .
2. set a on the bottom element ref.
3. when an event occurs, the method refof the object is called scrollintoview().

import {useeffect, useref, usestate} from 'react';

export default functionapp() {
  const bottomref = useref(null);

  const [messages, setmessages] = usestate([]);

  useeffect(() => {
    // 👇️ simulate chat messages flowing in
    setinterval(
      () =>
        setmessages(current => [
          ...current,
          'lorem ipsum dolor sit amet consectetur, adipisicing elit. porro, quaerat eum id obcaecati, magnam voluptatum dolorem sunt, omnis sed consectetur necessitatibus blanditiis ipsa? cumque architecto, doloribus mollitia velit non sint!',
        ]),
      600,
    );
  }, []);

  useeffect(() => {
    // 👇️ scroll to bottom every time messages change
    bottomref.current?.scrollintoview({behavior: 'smooth'});
  }, [messages]);

  return (
    <div><h2>top of the pageh2><div>
        {messages.map((message, index) => {
          return <pkey={index}>{message}p>;
        })}
        <divref={bottomref} />div>div>
  );
}

this code shows how to scroll to the bottom of the div each time a new chat message flows in.

the first call to useeffectthe hook simulates new messages appearing every 600 milliseconds.

we userefinitialize a ref using the hook.

useref()the hook can be passed an initial value as an argument. the hook returns a mutable ref object whose .current property is initialized to the passed argument.

note that we have to access currentthe property of the ref object to access the div element on which we set the ref attribute.

when we pass a ref prop to an element, for example

useeffect(() => {
  bottomref.current?.scrollintoview({behavior: 'smooth'});
}, [messages]);