Animating Content With React Spring

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

class TransitionArray extends PureComponent {
  constructor() {
    super()

    this.state = {
      items: NUM_TRANS
    }
  }

  componentDidUpdate(_, prevState) {
    const { items: currItems } = this.state
    const { items: prevItems } = prevState

    if (currItems.length === 0 && prevItems.length !== currItems.length) {
      setTimeout(() => {
        this.setState({
          items: NUM_TRANS
        })
      }, 2000)
    }
  }

  render() {
    return (
      <div style={{ display: "flex" }}>
        <Transition
          items={this.state.items}
          from={{ opacity: 0 }}
          enter={{ opacity: 1 }}
          leave={{ opacity: 0 }}
          delay={200}
          config={config.molasses}
          onRest={() => this.setState({ items: [] })}>
          {({ opacity }, item) => (
            <animated.div
              style={{
                opacity: opacity.to(item.op),
                transform: opacity
                  .to(item.trans)
                  .to((y) => `translate3d(0,${y}px,0)`)
              }}>
              {item.fig}
            </animated.div>
          )}
        </Transition>
      </div>
    )
  }
}