Animating content with react spring

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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>    )  }}