react-transition-group/stories/TransitionGroup.js

import React, { useEffect, useState } from 'react';
import { storiesOf } from '@storybook/react';

import TransitionGroup from '../src/TransitionGroup';

import CSSTransitionGroupFixture from './CSSTransitionGroupFixture';
import NestedTransition from './NestedTransition';
import StoryFixture from './StoryFixture';
import Fade, { FADE_TIMEOUT } from './transitions/CSSFadeForTransitionGroup';

storiesOf('Css Transition Group', module)
  .add('Animates on all', () => (
    <CSSTransitionGroupFixture
      description={`
        Should animate when items are added to the list but not when they are
        removed or on initial appear
      `}
      appear
      items={['Item number: 1']}
    >
      <Fade />
    </CSSTransitionGroupFixture>
  ))
  .add('Animates on enter', () => (
    <CSSTransitionGroupFixture
      description={`
        Should animate when items are added to the list but not when they are
        removed or on initial appear
      `}
      exit={false}
      timeout={{ enter: FADE_TIMEOUT }}
      items={['Item number: 1']}
    >
      <Fade />
    </CSSTransitionGroupFixture>
  ))
  .add('Animates on exit', () => (
    <CSSTransitionGroupFixture
      description={`
        Should animate when items are removed to the list but not when they are
        added or on initial appear
      `}
      items={['Item number: 1', 'Item number: 2', 'Item number: 3']}
    >
      <Fade enter={false} timeout={{ exit: FADE_TIMEOUT }} />
    </CSSTransitionGroupFixture>
  ))
  .add('Animates on appear', () => (
    <CSSTransitionGroupFixture
      description={`
        Should animate when items first mount but not when added or removed
      `}
      appear
      items={['Item number: 1', 'Item number: 2', 'Item number: 3']}
    >
      <Fade exit={false} enter={false} />
    </CSSTransitionGroupFixture>
  ))
  .add('Dynamic props', () => (
    <StoryFixture
      description={`
        Updates to children should not break animations
      `}
    >
      <DynamicTransition />
    </StoryFixture>
  ))
  .add('Re-entering while leaving', () => (
    <StoryFixture
      description={`
        Should animate on enter even while exiting
      `}
    >
      <ReEnterTransition />
    </StoryFixture>
  ))
  .add('Nested Transitions', () => <NestedTransition />);

class DynamicTransition extends React.Component {
  state = { count: 0 };
  handleClick = () => {
    this.setState({ hide: !this.state.hide });
  };

  componentDidMount() {
    this.interval = setInterval(() => {
      this.setState({ count: this.state.count + 1 });
    }, 700);
  }
  componentWillUnmount() {
    clearInterval(this.interval);
  }

  render() {
    const { hide, count } = this.state;
    return (
      <div>
        <button onClick={this.handleClick}>Toggle item</button>
        <TransitionGroup timeout={FADE_TIMEOUT}>
          {!hide && <Fade key="item">Changing! {count}</Fade>}
        </TransitionGroup>
      </div>
    );
  }
}

function ReEnterTransition() {
  const [hide, setHide] = useState(false);

  useEffect(() => {
    if (hide) {
      setTimeout(() => {
        console.log('re-entering!');
        setHide(false);
      }, 0.5 * FADE_TIMEOUT);
    }
  }, [hide]);

  return (
    <div>
      <button
        onClick={() => {
          setHide(true);
        }}
      >
        Remove and re-add
      </button>
      <TransitionGroup timeout={FADE_TIMEOUT}>
        {!hide && <Fade key="item">I'm entering!</Fade>}
      </TransitionGroup>
    </div>
  );
}