限制 animate.css 动画只能出现一次

Question

I am using animate.css and react-on-screen npm packages, react-on-screen package is to use TrackVisibility component so I can make a nice fade-in effect. But I only want the animation to be done once. But every time when I scroll back to the component and it reappears on the screen the animation is retaken, and it's not such a great UI. What should I do?

Answer 1

You can use the visible prop of the TrackVisibility component in conjunction with the useState hook, to keep track of whether the component has been animated or not. Once the component has been animated, you can use the animated prop to turn off the animation.

import { useState } from 'react';
import { TrackVisibility } from 'react-on-screen';

function MyComponent() {
  const [animated, setAnimated] = useState(false);

  return (
    <TrackVisibility onVisible={() => setAnimated(true)}>
      <div className={`my-component ${animated ? '' : 'animated fadeIn'}`}>
        <!-- ... -->
      </div>
    </TrackVisibility>
  );
}

In this example, the first time the MyComponent comes into view, the animated state variable is set to false, and the animation is applied. But when the MyComponent is scrolled out of view and then scrolled back into view, the animated state variable is already set to true, so the animation is not applied again.

It's also worth noting that if you want to make the animation only once you can use the once prop of the TrackVisibility component:

<TrackVisibility once>