Created
January 13, 2017 18:19
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React at 60fps Example 3
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export default class ScrollPane extends Component { | |
static contextTypes = { | |
registerPane: PropTypes.func.isRequired, | |
unregisterPane: PropTypes.func.isRequired | |
}; | |
componentDidMount() { | |
this.context.registerPane(this.el) | |
} | |
componentWillUnmount() { | |
this.context.unregisterPane(this.el) | |
} | |
render() { | |
return ( | |
<div ref={(el) => { this.el = el }}> | |
{this.props.children} | |
</div> | |
) | |
} | |
} | |
export default class ScrollContainer extends Component { | |
static childContextTypes = { | |
registerPane: PropTypes.func, | |
unregisterPane: PropTypes.func | |
} | |
getChildContext() { | |
return { | |
registerPane: this.registerPane, | |
unregisterPane: this.unregisterPane | |
} | |
} | |
panes = [] | |
registerPane = (node) => { | |
if (!this.findPane(node)) { | |
this.addEvents(node) | |
this.panes.push(node) | |
} | |
} | |
unregisterPane = (node) => { | |
if (this.findPane(node)) { | |
this.removeEvents(node) | |
this.panes.splice(this.panes.indexOf(node), 1) | |
} | |
} | |
addEvents = (node) => { | |
node.onscroll = this.handlePaneScroll.bind(this, node) | |
} | |
removeEvents = (node) => { | |
node.onscroll = null | |
} | |
findPane = node => this.panes.find(pane => pane === node) | |
handlePaneScroll = (node) => { | |
window.requestAnimationFrame(() => { | |
// Calculate new scrollTop positions | |
// for left and right panes based on | |
// DOM nodes and evt.target.scrollTop | |
// and set it directly on DOM nodes | |
this.panes.forEach((pane) => { | |
pane.scrollTop = … | |
}) | |
}) | |
} | |
render() { | |
return ( | |
<div> | |
<ScrollPane> | |
<ExpensiveComponent /> | |
</ScrollPane> | |
<ScrollPane> | |
<ExpensiveComponent /> | |
</ScrollPane> | |
</div> | |
) | |
} | |
} |
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