Shared Element Transitions (Sh El Tr -> Sheltr) for your React applications.

npm install @taito/react-sheltr

• What is it?
• Usage
• API Reference
• Examples

A shared element transition is a transition between two views where some element common for both views is used to smoothly bridge the transition. In practice there can be two (or more) different elements that are transformed (scaled and translated) so that it looks like one element that morphs from one state to the other.

Under the hood React Sheltr uses the FLIP technique to do the heavy lifting for calculating and animating the shared elements.

React Sheltr uses the official Context API introduced in React v16.3.0 so if you are using an older version of React than that then this module won't work 😕

Firstly add Sheltr provider somewhere up in the view hierarchy tree just like you would add your redux Provider or styled-components ThemeProvider. Note that it doesn't really need to be at the root level but somewhere above the SharedElement components that are used later.

import Sheltr from '@taito/react-sheltr';

<Sheltr>
  {/* other components go here */}
</Sheltr>

Then you can use SharedElement component to define and wire up your shared elements. This component use the render-prop / children as a function pattern to expose necessary props to the actual components that should be shared for the transition.

Here we have two related image components: Component A that starts the transition flow when it is clicked, which is the default behaviour, and Component B when it's unmounted.

import { SharedElement } from '@taito/react-sheltr';

// Component A
<SharedElement sharedId={id}>
  {sheltrProps => (
    <ImageA {...sheltrProps} />
  )}
</SharedElement>

// Component B
<SharedElement sharedId={id} startOnUnmount>
  {sheltrProps => (
    <ImageB {...sheltrProps} />
  )}
</SharedElement>

In some cases you might need to apply the individual sheltrProps to separate components or maybe compose them with some existing logic you have.

For this use case you can destruct the provided props and pick the ones you want. However, remember that you need to spread rest of the props to the component that should be shared.

<SharedElement sharedId={id}>
  {({ onClick, ...rest }) => (
    <Wrapper onClick={onClick}>
      <Image {...rest} />
    </Wrapper>
  )}
</SharedElement>

// Or

<SharedElement sharedId={id}>
  {({ onClick, ...rest }) => (
    <Wrapper onClick={() => {
      this.handleClick(someData);
      onClick();
    }}>
      <Image {...rest} />
    </Wrapper>
  )}
</SharedElement>

If you don't fancy the render-prop / children as a function pattern you can use withSheltr Higher Order Component to gain access to the underlying API and manually handle things that ShareElement would do for you.

import { withSheltr } from '@taito/react-sheltr';

class ComponentA extends Component {
  componentDidMount() {
    this.props.sheltr.transition();
  }

  handleClick = id => {
    this.props.sheltr.start(id);
  };

  render() {
    const { items, sheltr } = this.props;
    return (
      <Wrapper>
        {items.map(item => {
          return (
            <Item onClick={() => this.handleClick(item.id)}>
              <Thumbnail src={item.image} {...sheltr.getProps(item.id)} />
              {/* other things... */}
            </Item>
          );
        })}
      </Wrapper>
    );
  }
}

export default withSheltr(ComponentA);

import { withSheltr } from '@taito/react-sheltr';

class ComponentB extends Component {
  componentDidMount() {
    this.props.sheltr.transition();
  }

  componentWillUnmount() {
    this.props.sheltr.start(this.props.image.id);
  }

  render() {
    const { image, sheltr } = this.props;
    return (
      <Wrapper>
        <Img src={image.src} {...sheltr.getProps(image.id)} />
        {/* other things... */}
      </Wrapper>
    );
  }
}

export default withSheltr(ComponentB);

* = required.

To see more real-world-like examples that use react-router and styled-components check the examples folder for two quite common use cases for shared element transitions:

• List view with thumbnail images that morph into the header of the clicked item's detail view.
• Simple mosaic image gallery