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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

HTML

            
              <div id="app"></div>
            
          
!

CSS

            
              html, body {
  height: 100%;
}
            
          
!

JS

            
              /**

Expandable contains the reusable functionality/props used by different implementations of it. It takes a render prop as a way of managing the cross-cutting concerns.

Pros:
 - More obvious in render method that Expandable is wrapping this CustomExpandable component
 - Looks more "composable" (than a HOC)

Cons:
 - Edge case with PureComponents to be aware of https://reactjs.org/docs/render-props.html#be-careful-when-using-render-props-with-reactpurecomponent
 - Decreased testability (read https://medium.com/@PhilippSpo/i-agree-with-all-of-the-above-and-after-this-pitch-i-am-sold-on-render-prop-components-more-than-9e0e4305a4bf)

Read more: 
- Render props (React docs) https://reactjs.org/docs/render-props.html
- FaCCs as antipattern https://americanexpress.io/faccs-are-an-antipattern/

**/

class Expandable extends React.PureComponent {
  constructor(props) {
    super(props)
    this.state = {
      isOpen: false
    }
  }
  
  toggleOpen = () => {
    this.setState({ isOpen: !this.state.isOpen })
  }
  
  render() {
    const { isOpen } = this.state

    return this.props.render(isOpen, this.toggleOpen)
  }
}

class CustomExpandable extends React.Component {
  render() {
    const { isOpen, toggleOpen } = this.props
    return (
      <Expandable
        render={(isOpen, toggleOpen) => (
          <React.Fragment>
            {/* NOTE: in here you'd likely recycle a few Expandable subcomponents, like Expandable.Header and Expandable.Content */}
            <button onClick={toggleOpen}>Click me</button>
            { isOpen && (
              <p>Hellooooooooooooooooooooooooooooooooooooooooooooooooooo</p>
            )}
          </React.Fragment>
        )}
      />
    )
  }
}

/** ==================================================================================== **/

class App extends React.Component {
  render() {
    return (
      <CustomExpandable />
    )
  }
}

ReactDOM.render(
  <App />
  ,
  document.body
)
            
          
!
999px

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