Created
July 12, 2020 12:58
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Save 73nko/86534f54b880ceae66377d9dd8fe2c5e to your computer and use it in GitHub Desktop.
This package can render infinite list items without memory issues as it is using binary tree algorithm to remove and display elements while scrolling. check the demo and see how it works!
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import React, { Component } from 'react' | |
import PropTypes from 'prop-types' | |
import styles from './styles.css' | |
let containerRef= React.createRef(); | |
let dummyELRef= React.createRef(); | |
export default class ReactEternalList extends Component { | |
static propTypes = { | |
list: PropTypes.array, | |
component: PropTypes.func | |
} | |
state = { | |
list: [] | |
} | |
listItemHeightShouldUpdate = true; | |
minimumStackSize = 10; | |
scrollTop = 0; | |
containerHeight = window.innerHeight; | |
UNSAFE_componentWillReceiveProps(props) { | |
this.updateeternalList(props); | |
} | |
updateeternalList =(props=this.props)=> { | |
let shoudUpdate = this.isComponentUpdated(props); | |
shoudUpdate = this.setList(props) || shoudUpdate; | |
if(shoudUpdate) { | |
this.updateListDimension(); | |
this.updateListVisibility(); | |
} | |
} | |
componentDidMount() { | |
this.containerHeight = parseInt(containerRef.current.clientHeight, 10) | |
this.updateListItemHeight(); | |
this.updateeternalList(); | |
} | |
isComponentUpdated =props=> { | |
if(!this.componentSign || this.componentSign !== props.component.sign) { | |
props.component.sign = Date.now(); | |
this.componentSign = props.component.sign; | |
this.listItemHeightShouldUpdate = true; | |
return true; | |
} | |
return false; | |
} | |
updateNodeDimension =node=> { | |
if(node.parent) { | |
node.height = 0; | |
let temp; | |
for(let idx=0; idx < node.data.length; idx++) { | |
temp = this.updateNodeDimension(node.data[idx]); | |
node.height += temp.height; | |
} | |
node.top = node.data[0] ? node.data[0].top : 0; | |
node.bottom = node.top + node.height; | |
} else { | |
node.height = (node.data || []).length * this.listItemHeight; | |
node.top = this.totalTop; | |
node.bottom = node.top + node.height; | |
this.totalTop += node.height; | |
} | |
return node; | |
} | |
updateListDimension =()=> { | |
this.totalTop = 0; | |
this.updateNodeDimension(this.list); | |
} | |
isNodeVisible =node=> { | |
return (node.top <= this.scrollTop + (this.containerHeight * 1.5) ) && (node.bottom - (this.containerHeight * -0.5) >= this.scrollTop) | |
} | |
updateNodeVisibility =node=> { | |
node.visible = this.isNodeVisible(node); | |
if(node.visible && node.parent) { | |
for(let idx=0; idx< node.data.length; idx++) { | |
this.updateNodeVisibility(node.data[idx]); | |
} | |
} | |
} | |
updateListItemHeight =()=> { | |
if(this.listItemHeightShouldUpdate === true) { | |
this.listItemHeight = dummyELRef.current.clientHeight; | |
this.component = this.props.component; | |
this.listItemHeightShouldUpdate = false; | |
return true; | |
} | |
return false; | |
} | |
updateListVisibility =()=> { | |
let time = window.performance.now(); | |
this.updateNodeVisibility(this.list); | |
this.visibilityCheckTime = window.performance.now() - time; | |
this.setState({list: this.list || []}, ()=>{ | |
if(this.props.onUpdate) { | |
this.props.onUpdate({ | |
renderedComponentCount: this.renderedComponentCount, | |
renderedContainerCount: this.renderedContainerCount, | |
renderedDivCount: this.renderedContainerCount + this.renderedComponentCount, | |
visibilityCheckTime: this.visibilityCheckTime | |
}); | |
} | |
if(this.updateListItemHeight()) { | |
this.updateListDimension(); | |
this.updateListVisibility(); | |
} | |
}); | |
} | |
setList =(props=this.props)=> { | |
if(!this.list || this.list.sign !== props.list.sign) { | |
this.list = props.list || []; | |
this.list = this.recursiveSplit(this.list); | |
this.list.sign = props.list.sign = Date.now(); | |
containerRef.current.scrollTop = 0; | |
return true; | |
} | |
return false; | |
} | |
recursiveSplit =(data)=> { | |
if(data.length / 2 > this.minimumStackSize) { | |
let mid = Math.floor(data.length/2, 10); | |
let node = { | |
parent: true, | |
getParent: ()=> data, | |
data: [this.recursiveSplit(data.slice(0, mid)), this.recursiveSplit(data.slice(mid, data.length+1))] | |
} | |
return node; | |
} | |
return { | |
parent: false, | |
data | |
} | |
} | |
getList =()=> this.state.list || {}; | |
renderList =(node=this.getList())=> { | |
if(node.parent) { | |
this.renderedContainerCount += (node.data||[]).length; | |
return (node.data || []).map((item, index)=> { | |
return ( | |
<div className={styles.ilParent} key={index} style={{height: item.height}}> | |
{ item.visible ? this.renderList(item) : '' } | |
</div> | |
) | |
}); | |
} else { | |
this.renderedComponentCount += (node.data||[]).length; | |
return (node.data||[]).map((item, index)=> { | |
return this.component(item, index) | |
}); | |
} | |
} | |
handleScroll =e=> { | |
this.scrollTop = e.target.scrollTop; | |
clearTimeout(this.updationDebounce); | |
if(!this.updationInterval) { | |
this.updationInterval = setInterval(()=> { | |
this.updateListVisibility(); | |
}, this.props.updateRate || 100); | |
} | |
this.updationDebounce = setTimeout(()=>{ | |
this.updateListVisibility(); | |
clearInterval(this.updationInterval); | |
this.updationInterval = null; | |
}, this.props.updateRate || 100); | |
} | |
renderDummy =()=> { | |
return ( | |
<div className={styles.dummyContainer} ref={dummyELRef}> | |
{this.props.component((this.props.list||[])[0] || {})} | |
</div> | |
) | |
} | |
render() { | |
this.renderedComponentCount = 0; | |
this.renderedContainerCount = 0; | |
let renderedList = this.renderList(); | |
return ( | |
<div className={styles.eternalList} onScroll={this.handleScroll} ref={containerRef}> | |
<div className={styles.ilDummy}> | |
<this.renderDummy /> | |
</div> | |
<div className={styles.ilContainer}> | |
{renderedList} | |
</div> | |
</div> | |
) | |
} | |
} |
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