Develop Reference

React and Javascript: how can I move const out of function App()?

How can I move one or more const out of function App?
In the simple test App below, I'm using localStorage to store a value which determines if a div is dispayed. The handleToggle dismisses the div and stores a value in localStorage. Clearing localstorage and reloading shows the div again.
In a simple test App on localhost, this works. But in my more complex production App, I'm getting the error Invalid hook call. Hooks can only be called inside of the body of a function component , which has a myriad of fixes, one of which points out the issue may be that a const needs to be a separate function.
And so I'm thinking the issue is that I need to convert the two const to a function that can be placed right under the import blocks and out of the function App() block.
As a start, in this simple App, how can I move the two const out of function App()?
import './App.css';
import * as React from 'react';
function App() {
const [isOpen, setOpen] = React.useState(
JSON.parse(localStorage.getItem('is-open')) || false
);
const handleToggle = () => {
localStorage.setItem('is-open', JSON.stringify(!isOpen));
setOpen(!isOpen);
};
return (
<div className="App">
<header className="App-header">
<div>{!isOpen && <div>Content <button onClick={handleToggle}>Toggle</button></div>}</div>
</header>
</div>
);
}
export default App;
Edit: This is the full production file with Reza Zare's fix that now throws the error 'import' and 'export' may only appear at the top level on line 65:
import React from 'react';
import PropTypes from 'prop-types';
import ImmutablePropTypes from 'react-immutable-proptypes';
import ImmutablePureComponent from 'react-immutable-pure-component';
import BundleContainer from '../containers/bundle_container';
import ColumnLoading from './column_loading';
import DrawerLoading from './drawer_loading';
import BundleColumnError from './bundle_column_error';
import {
Compose,
Notifications,
HomeTimeline,
CommunityTimeline,
PublicTimeline,
HashtagTimeline,
DirectTimeline,
FavouritedStatuses,
BookmarkedStatuses,
ListTimeline,
Directory,
} from '../../ui/util/async-components';
import ComposePanel from './compose_panel';
import NavigationPanel from './navigation_panel';
import { supportsPassiveEvents } from 'detect-passive-events';
import { scrollRight } from '../../../scroll';
const componentMap = {
'COMPOSE': Compose,
'HOME': HomeTimeline,
'NOTIFICATIONS': Notifications,
'PUBLIC': PublicTimeline,
'REMOTE': PublicTimeline,
'COMMUNITY': CommunityTimeline,
'HASHTAG': HashtagTimeline,
'DIRECT': DirectTimeline,
'FAVOURITES': FavouritedStatuses,
'BOOKMARKS': BookmarkedStatuses,
'LIST': ListTimeline,
'DIRECTORY': Directory,
};
// Added const
const getInitialIsOpen = () => JSON.parse(localStorage.getItem('is-open')) || false;
const App = () => {
const [isOpen, setOpen] = React.useState(getInitialIsOpen());
const handleToggle = () => {
localStorage.setItem('is-open', JSON.stringify(!isOpen));
setOpen(!isOpen);
};
function getWeekNumber(d) {
d = new Date(Date.UTC(d.getFullYear(), d.getMonth(), d.getDate()));
d.setUTCDate(d.getUTCDate() + 4 - (d.getUTCDay()||7));
var yearStart = new Date(Date.UTC(d.getUTCFullYear(),0,1));
var weekNo = Math.ceil(( ( (d - yearStart) / 86400000) + 1)/7);
return [d.getUTCFullYear(), weekNo];
}
var result = getWeekNumber(new Date());
// errors out here: 'import' and 'export' may only appear at the top level.
export default class ColumnsArea extends ImmutablePureComponent {
static contextTypes = {
router: PropTypes.object.isRequired,
};
static propTypes = {
columns: ImmutablePropTypes.list.isRequired,
isModalOpen: PropTypes.bool.isRequired,
singleColumn: PropTypes.bool,
children: PropTypes.node,
};
// Corresponds to (max-width: $no-gap-breakpoint + 285px - 1px) in SCSS
mediaQuery = 'matchMedia' in window && window.matchMedia('(max-width: 1174px)');
state = {
renderComposePanel: !(this.mediaQuery && this.mediaQuery.matches),
}
componentDidMount() {
if (!this.props.singleColumn) {
this.node.addEventListener('wheel', this.handleWheel, supportsPassiveEvents ? { passive: true } : false);
}
if (this.mediaQuery) {
if (this.mediaQuery.addEventListener) {
this.mediaQuery.addEventListener('change', this.handleLayoutChange);
} else {
this.mediaQuery.addListener(this.handleLayoutChange);
}
this.setState({ renderComposePanel: !this.mediaQuery.matches });
}
this.isRtlLayout = document.getElementsByTagName('body')[0].classList.contains('rtl');
}
componentWillUpdate(nextProps) {
if (this.props.singleColumn !== nextProps.singleColumn && nextProps.singleColumn) {
this.node.removeEventListener('wheel', this.handleWheel);
}
}
componentDidUpdate(prevProps) {
if (this.props.singleColumn !== prevProps.singleColumn && !this.props.singleColumn) {
this.node.addEventListener('wheel', this.handleWheel, supportsPassiveEvents ? { passive: true } : false);
}
}
componentWillUnmount () {
if (!this.props.singleColumn) {
this.node.removeEventListener('wheel', this.handleWheel);
}
if (this.mediaQuery) {
if (this.mediaQuery.removeEventListener) {
this.mediaQuery.removeEventListener('change', this.handleLayoutChange);
} else {
this.mediaQuery.removeListener(this.handleLayouteChange);
}
}
}
handleChildrenContentChange() {
if (!this.props.singleColumn) {
const modifier = this.isRtlLayout ? -1 : 1;
this._interruptScrollAnimation = scrollRight(this.node, (this.node.scrollWidth - window.innerWidth) * modifier);
}
}
handleLayoutChange = (e) => {
this.setState({ renderComposePanel: !e.matches });
}
handleWheel = () => {
if (typeof this._interruptScrollAnimation !== 'function') {
return;
}
this._interruptScrollAnimation();
}
setRef = (node) => {
this.node = node;
}
renderLoading = columnId => () => {
return columnId === 'COMPOSE' ? <DrawerLoading /> : <ColumnLoading multiColumn />;
}
renderError = (props) => {
return <BundleColumnError multiColumn errorType='network' {...props} />;
}
render () {
const { columns, children, singleColumn, isModalOpen } = this.props;
const { renderComposePanel } = this.state;
if (singleColumn) {
return (
<div className='columns-area__panels'>
<div className='columns-area__panels__pane columns-area__panels__pane--compositional'>
<div className='columns-area__panels__pane__inner'>
{renderComposePanel && <ComposePanel />}
</div>
</div>
<div className='columns-area__panels__main'>
<div className='tabs-bar__wrapper'><div id='tabs-bar__portal' />
// output of getInitialIsOpen
<div class='banner'>
{!isOpen && <div>Content <button onClick={handleToggle}>Toggle</button></div>}
</div>
</div>
<div className='columns-area columns-area--mobile'>{children}</div>
</div>
<div className='columns-area__panels__pane columns-area__panels__pane--start columns-area__panels__pane--navigational'>
<div className='columns-area__panels__pane__inner'>
<NavigationPanel />
</div>
</div>
</div>
);
}
return (
<div className={`columns-area ${ isModalOpen ? 'unscrollable' : '' }`} ref={this.setRef}>
{columns.map(column => {
const params = column.get('params', null) === null ? null : column.get('params').toJS();
const other = params && params.other ? params.other : {};
return (
<BundleContainer key={column.get('uuid')} fetchComponent={componentMap[column.get('id')]} loading={this.renderLoading(column.get('id'))} error={this.renderError}>
{SpecificComponent => <SpecificComponent columnId={column.get('uuid')} params={params} multiColumn {...other} />}
</BundleContainer>
);
})}
{React.Children.map(children, child => React.cloneElement(child, { multiColumn: true }))}
</div>
);
}
}

How to update third party props value - Reactjs?

I'm using ant calendar which renders PanelBody(third party) component which has a prop call rowNum. Now I want to override this value to my custom value from my component:
import React from 'react';
import { Calendar } from 'antd';
import moment from 'moment';
import { Button } from '#material-ui/core';
import { getEventInfo, getQuest } from '../../../response/api';
import { EventInfo, Event } from '../../../response/type';
import { ConfigProvider } from 'antd';
import jaJP from 'antd/lib/locale/ja_JP';
interface State {
event_infos: EventInfo[];
events: Event[];
}
interface Props {
}
class EventCalendar extends React.Component<Props, State> {
constructor(props: Props) {
super(props);
this.state = {
event_infos: [],
events: []
};
}
componentDidMount() {
getEventInfo().then((item) => {
this.setState({event_infos: item});
});
getQuest().then((item) => {
this.setState({events: item});
});
}
getCorrectFormatDate = date => {
return moment(date, 'YYYY-MM-DD').format('YYYY-MM-DD');
}
getListEventInfoDate = value => {
let listData = [];
let listEventInfo = this.state.event_infos;
listEventInfo.map((item) => {
const startTime = this.getCorrectFormatDate(item.start_at);
const calendarTime = this.getCorrectFormatDate(value);
if (startTime === calendarTime) {
listData.push(item);
}
return listData;
});
return listData || [];
}
getListEventDate = value => {
let listData = [];
let listEvent = this.state.events;
listEvent.map((item) => {
const startTime = this.getCorrectFormatDate(item.start_at);
const calendarTime = this.getCorrectFormatDate(value);
if (startTime === calendarTime) {
listData.push(item);
}
return listData;
});
return listData || [];
}
dateCellRender = value =>{
const listEventInfos = this.getListEventInfoDate(value);
const listEvents = this.getListEventDate(value)
return (
<ul className="events-calendar">
{listEventInfos.map((item, i) => <img key={i} src={item.image} alt="event_info" />)}
{listEvents.map((item, i) => <Button key={i} variant="outlined" color="primary" className="button-event">{item.name}</Button>)}
</ul>
)
}
render() {
moment.locale("ja");
return(
<ConfigProvider locale={jaJP}>
<Calendar
dateCellRender={this.dateCellRender}
className="hide-header"
validRange={[moment('2020-12-13', 'YYYY-MM-DD'), moment('2021-01-16', 'YYYY-MM-DD')]}
defaultValue={moment('2020-12-13')}
/>
</ConfigProvider>
)
}
};
export default EventCalendar;
This component render Calendar which renders PanelBody. I tried to create a duplicated component then overrided the prop value, imported it to EventCalendar, but it cannot update the props value as expected. Is it my approach wrong? Any suggestion for this issue?

Reactjs: React-router-dom Cannot Read Property Push of Undefined

Before you conclude that i have not combed stackoverflow very well, i will like to state that i have done that but i have not yet gotten the solution.
Good day guys, i have been having this issue for days, i was trying to push after clicking on a button but i cannot. I then tried to console.log this.props in the componentDidMount and it was showing an empty object.
This is the App.js file
import React, { Component } from 'react';
import { Route, Switch } from 'react-router-dom';
import Layout from './hoc/Layout/Layout';
import BurgerBuilder from './containers/BurgerBuilder/BurgerBuilder';
import Checkout from './containers/Checkout/Checkout';
class App extends Component {
render () {
return (
<div>
<Layout>
<Switch>
<Route path="/" exact render = {routeProps => (
<BurgerBuilder {...routeProps} />
)}
/>
<Route path="/checkout" exact component={Checkout} />
</Switch>
</Layout>
</div>
);
}
}
export default App;
This is the burger-builder component
import React, { Component } from 'react'
import Aux from '../../hoc/Aux_/Aux_'
import Burger from '../../components/Burger/Burger'
import BuildControls from '../../components/Burger/BuildControls/BuildControls'
import Modal from '../../components/UI/Modal/Modal'
import OrderSummary from '../../components/Burger/OrderSummary/OrderSummary'
import Spinner from '../../components/UI/Spinner/Spinner'
import withErrorHandler from '../../hoc/withErrorHandler/withErrorHandler'
import axios from '../../axios-orders'
const INGREDIENT_PRICES = {
salad: 0.5,
cheese: 0.4,
meat: 1.3,
bacon: 0.7
}
class BurgerBuilder extends Component{
constructor(props){
super(props);
this.state = {
ingredients:null,
totalPrice:4,
purchaseable:false,
purchasing:false,
loading:false,
error: false
}
}
componentDidMount(){
console.log(this.props)
axios.get('/ingredients')
.then(response => {
this.setState({ingredients : response.data});
})
.catch((error) => {
this.setState({error: true})
})
}
updatePurchaseState = (ingredients) => {
const sum = Object.keys(ingredients)
.map((igKey) => (
ingredients[igKey]
))
.reduce((sum, el) =>{
return sum + el
} ,0)
this.setState({purchaseable: sum > 0})
}
addIngredientHandler = (type) => {
const oldCount = this.state.ingredients[type];
const updatedCount = oldCount + 1;
const updateIngredients = {
...this.state.ingredients
};
updateIngredients[type] = updatedCount;
const priceAddition = INGREDIENT_PRICES[type];
const oldPrice = this.state.totalPrice
const newPrice = oldPrice + priceAddition;
this.setState({totalPrice: newPrice, ingredients: updateIngredients},
this.updatePurchaseState(updateIngredients)
)
}
removeIngredientHandler = (type) => {
const oldCount = this.state.ingredients[type];
if(oldCount <= 0){
return ;
}
const updatedCount = oldCount - 1;
const updateIngredients = {
...this.state.ingredients
};
updateIngredients[type] = updatedCount;
const priceDeduction = INGREDIENT_PRICES[type];
const oldPrice = this.state.totalPrice
const newPrice = oldPrice - priceDeduction;
this.setState({totalPrice: newPrice, ingredients: updateIngredients},
this.updatePurchaseState(updateIngredients)
)
}
purchaseHandler = () => {
this.setState({purchasing:true})
}
purchaseCancelHandler = () => {
this.setState({purchasing:false})
}
purchaseContinueHandler = () => {
// this.setState({loading:true})
// alert('You Continued')
// const order = {
// ingredients: this.state.ingredients,
// price: this.state.totalPrice,
// customer:{
// name:'Durojaye Peter',
// address:{
// street:'Ire-Akari Estate 2',
// zipCode: '41351',
// country: 'Nigeria'
// },
// email:'oluleyepeters#gmail.com',
// },
// deliveryMethod:'fastest'
// }
// axios.post('/orders',order)
// .then(response => {
// this.setState({loading:false, purchasing:false})
// })
// .catch(error => {
// this.setState({loading:false, purchasing:false})
// })
this.props.history.push('/')
}
render(){
const disabledInfo = {
...this.state.ingredients
};
for(let key in disabledInfo){
disabledInfo[key] = disabledInfo[key] <= 0
}
let orderSummary = null
let burger = this.state.error ? <p>Ingredients cannot be loaded</p> : <Spinner />
if(this.state.ingredients !== null){
burger = (
<Aux>
<Burger ingredients={this.state.ingredients}/>
<BuildControls
ingredientAdded={this.addIngredientHandler}
ingredientRemoved={this.removeIngredientHandler}
disabled={disabledInfo}
purchaseable={this.state.purchaseable}
price= {this.state.totalPrice}
ordered={this.purchaseHandler}
/>
</Aux>
);
orderSummary = <OrderSummary
ingredients={this.state.ingredients}
purchaseCanceled = {this.purchaseCancelHandler}
purchaseContinued = {this.purchaseContinueHandler}
price={this.state.totalPrice}
/>
}
if(this.state.loading){
orderSummary = <Spinner />
}
return(
<Aux>
<Modal show={this.state.purchasing} modalClosed={this.purchaseCancelHandler}>
{orderSummary}
</Modal>
{burger}
</Aux>
)
}
}
export default withErrorHandler(BurgerBuilder, axios)
As it is shown in the code,i was trying to console.log this.props in the purchaseContinueHandler but it keeps showing an empty object.
Thanks a lot guys any help will be appreciated.

Have you tried giving the basename to the Layout component. Also try removing Exact.
<Layout basename={process.env.REACT_APP_BASE_PATH}>
<Switch>
<Route path="/" render = {routeProps => (
<BurgerBuilder {...routeProps} />
)}
/>
</Layout

How can the render be synced with the state on pagination click with react?

I created a suggestions search and its built to break up the fetch based on the current page. The state is console.loged correctly, but the render is one page click event behind. This is obviously not the behavior we want. It seems like the state is being updated fine. I have tried to refactor the code difference ways, and even tried this.forceUpdate()
Here is the code
SearchOrderBar.js
import React, { Component } from "react";
import {Input, Label, Table, Icon, Header, Menu} from 'semantic-ui-react';
import "./SearchOrderBar.css";
// import { resolve } from "dns";
// import PropTypes from 'prop-types';
import Pagination from '../Search/Pagination';
class SearchOrderBar extends Component {
constructor(props) {
super(props);
this.text = "";
this.state = {
suggestions: [],
addToQuery: false,
Query: [],
pagesNeeded: 0,
page: 1
};
let searchTerm = null;
const {pageLimit = null, keyTimer = null, } = props;
this.pageLimit = typeof pageLimit === 'number' ? pageLimit : 10;
this.handlePageClick = this.handlePageClick.bind(this);
this.fetchCallBack = this.fetchCallBack.bind(this);
// this.addToQuery = this.addToQuery.bind(this);
this.keyUpHandler = this.keyUpHandler.bind(this);
this.keyDownHandler = this.keyDownHandler.bind(this);
}
handlePageClick(page){
this.forceUpdate();
this.setState({
page: page
})
this.fetchCallBack();
}
//This fetch should be called in a dynamic switch case
fetchCallBack() {
let y = this.pageLimit;
let x = this.state.page > 1 ? (this.pageLimit*this.state.page) - this.pageLimit : 0;
// Return a promise
return new Promise((resolve, reject) => {
let searchTerm = this.searchTerm;
return fetch(`http://localhost:5000/api/searchorders/${searchTerm}/${x}/${y}`)
.then(res => {
if (!res.ok) {
throw res;
}
// Convert serialized response into json
return res.json()
}).then(data => {
//Use data
let searchTerm = data.map(data => {
let rData = {};
rData = data;
return rData;
})
this.item = searchTerm;
//console.log('here from callback')
this.setState({
suggestions: []
})
return searchTerm;
}).then( data => {
// console.log(this.totalRecords)sd
//console.log(data)
if (searchTerm.length === 0) {
this.setState({
suggestions: [],
rangeCount_URL: `http://localhost:5000/api/searchorderscount/${searchTerm}`
});
} else {
const suggestions = data.filter(function(v){
if(Object.values(v).includes(searchTerm.toLowerCase()) !== -1 || Object.values(v).includes(searchTerm.toUpperCase()) !== -1){
return v
}
})
console.log(suggestions)
this.text = searchTerm;
this.setState({ suggestions: suggestions.sort()});
}
})
})
}
pageCountCallBack(){
return new Promise((resolve, reject) => {
let searchTerm = this.searchTerm;
return fetch(`http://localhost:5000/api/searchorderscount/${searchTerm}/`)
.then(res => {
if (!res.ok) {
throw res;
}
// Convert serialized response into json
return res.json()
}).then(data => {
//Use data
let searchTerm = data.map(data => {
let rData = {};
rData = data;
return rData;
})
this.item = searchTerm;
// console.log('here from Page Count callback')
this.renderSuggestions();
resolve(searchTerm)
})
})
}
keyUpHandler = (e) => {
if(e.target.value.length >= 3){
this.keyTimer = setTimeout(this.countFetch(e), 1500);
} else {
this.setState(() => {
return {
suggestions : [],
pagesNeeded : 0
}
})
clearTimeout(this.keyTimer);
}
}
keyDownHandler = (e) => {
clearTimeout(this.keyTimer);
}
//Any time text is changed in the text field
countFetch = (e) => {
const value = e.target.value;
this.searchTerm = value;
this.pageCountCallBack().then(data => {
const totalRecords = data[0].rows;
this.setState(() => {
return {pagesNeeded : Math.ceil(totalRecords / this.pageLimit)}
})
//console.log("total" + totalRecords);
//console.log("page limit"+this.pageLimit);
//console.log("Needed" + this.state.pagesNeeded );
})
this.fetchCallBack();
}
renderSuggestions() {
//const { suggestions } = this.state;
const tableStyle = {
'tableLayout': 'fixed',
'overflowWrap': 'break-word'
}
return (
<Table style={tableStyle} celled>
{this.state.suggestions.length === 0 ?
(<Table.Body>
<Table.Cell colSpan="7">
<div className="ui fluid warning icon message">
<Icon name="exclamation triangle" size="huge" color="orange"/>
<div className="content">
<Header>No Records Found</Header>
<p>Try Seaching by one of the following:</p>
<ul>
<dt>Name</dt>
<dt>Order Number</dt>
<dt>Address (Shipping or Billing )</dt>
<dt>Phone Number</dt>
<dt>Email</dt>
</ul>
</div>
</div>
</Table.Cell>
</Table.Body>)
: (
<>
<Table.Header>
<Table.Row>
<Table.HeaderCell>Order#</Table.HeaderCell>
<Table.HeaderCell>Billing Address</Table.HeaderCell>
<Table.HeaderCell>Shipping Address</Table.HeaderCell>
<Table.HeaderCell>Email</Table.HeaderCell>
<Table.HeaderCell>Phone Number</Table.HeaderCell>
<Table.HeaderCell>Sales Channel</Table.HeaderCell>
<Table.HeaderCell>Order Date</Table.HeaderCell>
</Table.Row>
</Table.Header>
<Table.Body>
{this.state.suggestions.map((item, index) => (
<Table.Row className="hoverRow">
<Table.Cell key={index} onClick={() => this.addToQuery(item)}>
{item.customerPO}
</Table.Cell>
<Table.Cell>
{item.billToAddress}
</Table.Cell>
<Table.Cell>{item.shipToAddress}</Table.Cell>
<Table.Cell>{item.email}</Table.Cell>
<Table.Cell>{item.phone}</Table.Cell>
<Table.Cell>{item.customerContact}</Table.Cell>
<Table.Cell>{item.dateCreated}</Table.Cell>
</Table.Row>
))}
</Table.Body>
</>
)
}
<Pagination key={this.state.pagesNeeded} tableCols="7" pagesNeeded={this.state.pagesNeeded} btnLimit={5} pageClick={this.handlePageClick} currPage={this.state.page} pageLimit={this.pageLimit}/>
</Table>
);
}
handleIconClick(){
console.log('icon clicked ' + this.state.Query )
}
render() {
const {text} = this.state
//console.log(this.state)
return (
<>
<div className="App-Component">
<div className="App-Search">
<Input icon={{ name: 'search', circular: true, link: true, onClick: () => this.handleIconClick() }} placeholder="Search" value={text} type="text" onKeyUp={this.keyUpHandler} onKeyDown={this.keyDownHandler} className="App-Search"/>
{this.renderSuggestions()}
</div>
</div>
</>
);
}
}
export default SearchOrderBar;
Here is the pagination but I don't think this matters as much for the solution. It is relevant for the page button click.
import React, {Component} from 'react';
import {Input, Label, Table, Icon, Header, Menu} from 'semantic-ui-react'
/**
* Helper Method for creating a range of Numbers
* Range )( )
*/
const range = (from, to, step = 1) => {
let i = from;
const range = [];
while (i<=to) {
range.push(i);
i+=step;
}
}
export default class Pagination extends Component {
constructor(props){
super(props)
const { totalRecords = null, pageNeighbours = 0, rangeCount_URL = this.props.rangeCount_URL, pageArray = [] } = props;
this.pageArray = typeof pageArray === 'array' ? pageArray : [];
}
renderPagination = () => {
//console.log("hello from pagination");
let n = this.props.pagesNeeded;
let pArray = [];
let page = this.props.currPage;
//console.log(n)
if (page > 1){
pArray.push(<Menu.Item as='a' icon onClick={() => this.props.pageClick(page-1)}>
<Icon name='chevron left' />
</Menu.Item>)
}
for(let i = (page >1 ? page-1: page); pArray.length < (page > this.props.btnLimit ? this.props.btnLimit+1 : this.props.btnLimit); i++){
//console.log(i);
pArray.push(<Menu.Item index={i} className={i == page ? 'active' : ''} onClick={() => this.props.pageClick(i)} as='a'>{i}</Menu.Item>)
}
if (page < n){
pArray.push(<Menu.Item as='a' icon onClick={() => this.props.pageClick(page+1)}>
<Icon name='chevron right' />
</Menu.Item>)
}
this.pageArray = pArray;
return pArray;
}
render(){
const pageCount = (() => {
const totalRecords = this.totalRecords;
if(totalRecords > 0){
return (this.totalPages = Math.ceil(this.totalRecords / this.props.pageLimit))
}
})();
//console.log(this.pageArray);
return(
<Table.Footer>
{ this.props.pagesNeeded > 1 &&
<Table.Row>
<Table.HeaderCell colSpan={this.props.tableCols}>
<Menu floated='right' pagination>
{this.renderPagination()}
</Menu>
</Table.HeaderCell>
</Table.Row>
}
</Table.Footer>
)
}
}

setState is batched and invoked asynchronously, meaning when you call to this.setState({page}) then read this.state.page in fetchCallBack you probably get the "old" page and not the new page.
Either pass the page directly to fetchCallBack
this.fetchCallBack(page)
And read the page from it and not directly from the state
Or call it as the second argument of setState which is a callback that react will invoke right after the state has been updated.
this.setState({ page }, this.fetchCallBack);

At the point fetchCallBack is called, this.state.page is not updated yet because setState is called asynchronously, that's why it's using the old value. Try this:
handlePageClick(page) {
this.setState({ page }, this.fetchCallBack);
}
The callback syntax allows you to run the function in the next iteration.

React infinite scroll component performance

I have written the following infinite scroll component in React:
import React from 'react'
import { uniqueId, isUndefined, hasVerticalScrollbar, hasHorizontalScrollbar, isInt, throttle } from '../../../js/utils';
export default class BlSimpleInfiniteScroll extends React.Component {
constructor(props) {
super(props)
this.handleScroll = this.handleScroll.bind(this)
this.itemsIdsRefsMap = {}
this.isLoading = false
this.node = React.createRef()
}
componentDidMount() {
const {
initialId
} = this.props
let id
if (initialId) {
if (typeof initialId === "function") {
id = initialId()
}
else {
id = initialId
}
this.scrollToId(id)
}
}
componentDidUpdate(prevProps) {
if (
this.isLoading
&&
prevProps.isInfiniteLoading
&&
!this.props.isInfiniteLoading
) {
const axis = this.axis()
const scrollProperty = this.scrollProperty(axis)
const offsetProperty = this.offsetProperty(axis)
this.scrollTo(scrollProperty, this.node.current[offsetProperty])
this.isLoading = false
}
}
itemsRenderer(items) {
const length = items.length
let i = 0
const renderedItems = []
for (const item of items) {
renderedItems[i] = this.itemRenderer(item.id, i, length)
i++
}
return renderedItems
}
itemRenderer(id, i, length) {
const {
itemRenderer,
isInfiniteLoading,
displayInverse
} = this.props
let renderedItem = itemRenderer(id, i)
if (isInfiniteLoading) {
if (!displayInverse && (i == length - 1)) {
renderedItem = this.standardLoadingComponentWrapperRenderer(id, renderedItem)
}
else if (i == 0) {
renderedItem = this.inverseLoadingComponentWrapperRenderer(id, renderedItem)
}
}
const ref = this.itemsIdsRefsMap[id] || (this.itemsIdsRefsMap[id] = React.createRef())
return (
<div className="bl-simple-infinite-scroll-item"
key={id}
ref={ref}>
{renderedItem}
</div>
)
}
loadingComponentRenderer() {
const {
loadingComponent
} = this.props
return (
<div className="bl-simple-infinite-scroll-loading-component"
key={uniqueId()}>
{loadingComponent}
</div>
)
}
loadingComponentWrapperRenderer(id, children) {
return (
<div className="bl-simple-infinite-scroll-loading-component-wrapper"
key={id}>
{children}
</div>
)
}
standardLoadingComponentWrapperRenderer(id, renderedItem) {
return this.loadingComponentWrapperRenderer(id, [
renderedItem,
this.loadingComponentRenderer()
])
}
inverseLoadingComponentWrapperRenderer(id, renderedItem) {
return this.loadingComponentWrapperRenderer(id, [
this.loadingComponentRenderer(),
renderedItem
])
}
axis() {
return this.props.axis === 'x' ? 'x' : 'y'
}
scrollProperty(axis) {
return axis == 'y' ? 'scrollTop' : 'scrollLeft'
}
offsetProperty(axis) {
return axis == 'y' ? 'offsetHeight' : 'offsetWidth'
}
scrollDimProperty(axis) {
return axis == 'y' ? 'scrollHeight' : 'scrollWidth'
}
hasScrollbarFunction(axis) {
return axis == 'y' ? hasVerticalScrollbar : hasHorizontalScrollbar
}
scrollToStart() {
const axis = this.axis()
this.scrollTo(
this.scrollProperty(axis),
!this.props.displayInverse ?
0
:
this.scrollDimProperty(axis)
)
}
scrollToEnd() {
const axis = this.axis()
this.scrollTo(
this.scrollProperty(axis),
!this.props.displayInverse ?
this.scrollDimProperty(axis)
:
0
)
}
scrollTo(scrollProperty, scrollPositionOrPropertyOfScrollable) {
const scrollableContentNode = this.node.current
if (scrollableContentNode) {
scrollableContentNode[scrollProperty] = isInt(scrollPositionOrPropertyOfScrollable) ?
scrollPositionOrPropertyOfScrollable
:
scrollableContentNode[scrollPositionOrPropertyOfScrollable]
}
}
scrollToId(id) {
if (this.itemsIdsRefsMap[id] && this.itemsIdsRefsMap[id].current) {
this.itemsIdsRefsMap[id].current.scrollIntoView()
}
}
handleScroll() {
const {
isInfiniteLoading,
infiniteLoadBeginEdgeOffset,
displayInverse
} = this.props
if (
this.props.onInfiniteLoad
&&
!isInfiniteLoading
&&
this.node.current
&&
!this.isLoading
) {
const axis = this.axis()
const scrollableContentNode = this.node.current
const scrollProperty = this.scrollProperty(axis)
const offsetProperty = this.offsetProperty(axis)
const scrollDimProperty = this.scrollDimProperty(axis)
const currentScroll = scrollableContentNode[scrollProperty]
const currentDim = scrollableContentNode[offsetProperty]
const scrollDim = scrollableContentNode[scrollDimProperty]
const finalInfiniteLoadBeginEdgeOffset = !isUndefined(infiniteLoadBeginEdgeOffset) ?
infiniteLoadBeginEdgeOffset
:
currentDim / 2
let thresoldWasReached = false
let memorizeLastElementBeforeInfiniteLoad = () => { }
if (!displayInverse) {
thresoldWasReached = currentScroll >= (scrollDim - finalInfiniteLoadBeginEdgeOffset)
}
else {
memorizeLastElementBeforeInfiniteLoad = () => {
// TODO
}
thresoldWasReached = currentScroll <= finalInfiniteLoadBeginEdgeOffset
}
if (thresoldWasReached) {
this.isLoading = true
memorizeLastElementBeforeInfiniteLoad()
this.props.onInfiniteLoad()
}
}
}
render() {
const {
items
} = this.props
return (
<div className="bl-simple-infinite-scroll"
ref={this.node}
onScroll={this.handleScroll}
onMouseOver={this.props.onInfiniteScrollMouseOver}
onMouseOut={this.props.onInfiniteScrollMouseOut}
onMouseEnter={this.props.onInfiniteScrollMouseEnter}
onMouseLeave={this.props.onInfiniteScrollMouseLeave}>
{this.itemsRenderer(items)}
</div>
)
}
}
And I use it like this in a chat app I am writing:
...
<BlSimpleInfiniteScroll items={chat.messages}
ref={this.infiniteScrollComponentRef}
initialId={() => lastOfArray(chat.messages).id}
itemRenderer={(id, i) => this.messageRenderer(id, i, chat.messages)}
loadingComponent={<BlLoadingSpinnerContainer />}
isInfiniteLoading={isChatLoading}
displayInverse
infiniteLoadBeginEdgeOffset={void 0}
infiniteLoadingBeginBottomOffset={void 0}
onInfiniteLoad={() => this.props.onLoadPreviousChatMessages(chat.id)}
onInfiniteScrollMouseEnter={this.handleInfiniteScrollMouseEnter}
onInfiniteScrollMouseLeave={this.handleInfiniteScrollMouseLeave} />
...
The problem is that as soon as I scroll until the thresold and onInfiniteLoad is called, before the loading spinner is showed and after the data has been loaded the scroll freezes and the component becomes unresponsive.
How can I resolve this issue?
When I render the spinner container and after the previous loaded messages, shouldn't React just append the new divs retaining the previously added items in order to maintain the component performant?
If not, what key concepts of React I am missing?
Thank you for your attention!
UPDATE: Here are the additional components:
BlOrderChat represents a chat window and renders BlSimpleInfiniteScroll:
import React from 'react'
import BlOrderChatMessage from './BlOrderChatMessage';
import { isEmpty, uniqueId } from '../../../js/utils';
import { chatSelector } from '../selectors';
import BlLoadingSpinnerContainer from '../../core/animation/loading/BlLoadingSpinnerContainer';
import BlSimpleInfiniteScroll from '../../core/scroll/BlSimpleInfiniteScroll';
export default class BlOrderChat extends React.Component {
static BL_ORDER_CHAT_MESSAGE_ID_ATTR_PREFIX = 'blOrderChatMessage'
constructor(props) {
super(props)
this.messageRenderer = this.messageRenderer.bind(this)
this.infiniteScrollComponentRef = React.createRef()
}
scrollToBottom() {
this.infiniteScrollComponentRef.current && this.infiniteScrollComponentRef.current.scrollToStart()
}
messageRenderer(messageId, index, messages) {
const {
currentUser, chat
} = this.props
const message = messages[index]
const length = messages.length
const fromUser = chat.users.items[message.from_user_id]
const itemComponentRender = (children) => (
<div key={messageId}>
{children}
</div>
)
const messageIdAttr = `${BlOrderChat.BL_ORDER_CHAT_MESSAGE_ID_ATTR_PREFIX}${message.id}`
const renderMessageComponent = () => (
<BlOrderChatMessage id={messageIdAttr}
key={uniqueId() + message.id}
message={message.message}
sentUnixTs={message.sent_unix_ts}
currentUser={currentUser}
fromUser={fromUser}
usersInvolvedInChatLength={chat.users.order.length} />
)
let children = []
if (index === 0) {
// First message.
children = [
<div key={uniqueId()} className="bl-padding"></div>,
renderMessageComponent()
]
}
else if (index === length - 1) {
// Last message.
children = [
renderMessageComponent(onComponentDidMount),
<div key={uniqueId()} className="bl-padding"></div>
]
}
else {
// Message in the middle.
children = [
renderMessageComponent()
]
}
return itemComponentRender(children)
}
render() {
const {
chat: propsChat, isChatLoading,
currentUser
} = this.props
const chat = chatSelector(propsChat, currentUser)
const chatHasMessages = chat && !isEmpty(chat.messages)
return (
<div className="bl-order-chat">
<div className="bl-order-chat-header">
// ...
</div>
<div className="bl-order-chat-content">
{
(chatHasMessages &&
<div className="bl-order-chat-content-inner">
<div className="bl-order-chat-infinite-scroll">
<BlSimpleInfiniteScroll items={chat.messages}
ref={this.infiniteScrollComponentRef}
initialId={() => lastOfArray(chat.messages).id}
itemRenderer={(id, i) => this.messageRenderer(id, i, chat.messages)}
loadingComponent={<BlLoadingSpinnerContainer />}
isInfiniteLoading={isChatLoading}
displayInverse
infiniteLoadBeginEdgeOffset={void 0}
infiniteLoadingBeginBottomOffset={void 0}
onInfiniteLoad={() => this.props.onLoadPreviousChatMessages(chat.id)}
onInfiniteScrollMouseEnter={this.handleInfiniteScrollMouseEnter}
onInfiniteScrollMouseLeave={this.handleInfiniteScrollMouseLeave} />
</div>
</div>
)
||
(isChatLoading &&
<BlLoadingSpinnerContainer />
)
}
</div>
<div className="bl-order-chat-footer">
// ...
</div>
</div>
)
}
}
BlOrderChatBox, contains BlOrderChat:
import React from 'react'
import BlOrderChat from './BlOrderChat';
import BlAlert from '../../core/alert/BlAlert';
import BlLoadingSpinnerContainer from '../../core/animation/loading/BlLoadingSpinnerContainer';
export default class BlOrderChatBox extends React.Component {
constructor(props) {
super(props)
this.node = React.createRef()
}
render() {
const {
ordId, currentChat,
isCurrentChatLoading, currentUser,
err
} = this.props
return (
<div className="bl-order-chat-box" ref={this.node}>
<div className="bl-order-chat-box-inner">
{
(err &&
<BlAlert type="error" message={err} />)
||
(currentChat && (
// ...
<div className="bl-order-chat-box-inner-chat-content">
<BlOrderChat ordId={ordId}
chat={currentChat}
isChatLoading={isCurrentChatLoading}
onLoadPreviousChatMessages={this.props.onLoadPreviousChatMessages}
currentUser={currentUser} />
</div>
))
||
<BlLoadingSpinnerContainer />
}
</div>
</div>
)
}
}
And here is the component which renders BlOrderChatBox (it is the topmost stateful component):
import React from 'react'
import { POSTJSON } from '../../../js/ajax';
import config from '../../../config/config';
import { newEmptyArrayAble, arrayToArrayAbleItemsOrder, arrayAbleItemsOrderToArray, mergeArrayAbles, newArrayAble, firstOfArrayAble, isArrayAble } from '../../../js/data_structures/arrayable';
export default class BlOrderChatApp extends React.Component {
static NEW_CHAT_ID = 0
static MAX_NUMBER_OF_MESSAGES_TO_LOAD_PER_AJAX = 30
constructor(props) {
super(props)
this.currentUser = globals.USER
this.lastHandleSendMessagePromise = Promise.resolve()
this.newMessagesMap = {}
this.typingUsersDebouncedMap = {}
// Imagine this comes from a database.
const chat = {
// ...
}
const initialState = {
chats: newArrayAble(this.newChat(chat)),
currentChatId: null,
shouldSelectUserForNewChat: false,
newChatReceivingUsers: newEmptyArrayAble(),
isChatListLoading: false,
isCurrentChatLoading: false,
popoverIsOpen: false,
popoverHasOpened: false,
err: void 0,
focusSendMessageTextarea: false,
newChatsIdsMap: {},
currentChatAuthActs: {},
BlOrderChatComponent: null,
}
this.state = initialState
this.handleLoadPreviousChatMessages = this.handleLoadPreviousChatMessages.bind(this)
}
POST(jsonData, callback) {
let requestJSONData
if (typeof jsonData === "string") {
requestJSONData = {
action: jsonData
}
}
else {
requestJSONData = jsonData
}
return POSTJSON(config.ORDER_CHAT_ENDPOINT_URI, {
...requestJSONData,
order_chat_type: this.props.orderChatType,
}).then(response => response.json()).then(json => {
this.POSTResponseData(json, callback)
})
}
POSTResponseData(data, callback) {
if (data.err) {
this.setState({
err: data.err
})
}
else {
callback && callback(data)
}
}
newChat(chat) {
const newChat = {
id: (chat && chat.id) || BlOrderChatApp.NEW_CHAT_ID,
ord_id: this.props.ordId,
users: (chat && chat.users && (isArrayAble(chat.users) ? chat.users : arrayToArrayAbleItemsOrder(chat.users))) || newEmptyArrayAble(),
messages: (chat && chat.messages && (isArrayAble(chat.messages) ? chat.messages : arrayToArrayAbleItemsOrder(chat.messages))) || newEmptyArrayAble(),
first_message_id: (chat && chat.first_message_id) || null,
typing_users_ids_map: (chat && chat.typing_users_ids_map) || {},
}
return newChat
}
isChatNew(chat) {
return (
chat
&&
(chat.id == BlOrderChatApp.NEW_CHAT_ID || this.state.newChatsIdsMap[chat.id])
)
}
loadPreviousChatMessages(chatId, lowestMessageIdOrNull, makeChatIdCurrent) {
this.POST({
act: 'loadPreviousChatMessages',
chat_id: chatId,
lowest_message_id: lowestMessageIdOrNull,
max_number_of_messages_to_load: BlOrderChatApp.MAX_NUMBER_OF_MESSAGES_TO_LOAD_PER_AJAX
}, json => {
this.setState(prevState => {
const chat = prevState.chats.items[chatId]
const messages = arrayToArrayAbleItemsOrder(json.messages)
const newChat = {
...chat,
messages: mergeArrayAbles(messages, chat.messages)
}
const chats = mergeArrayAbles(prevState.chats, newArrayAble(newChat))
return {
...(makeChatIdCurrent ?
{
currentChatId: chatId,
focusSendMessageTextarea: true,
}
:
{
currentChatId: prevState.currentChatId,
}
),
chats,
isCurrentChatLoading: false,
}
})
})
}
loadPreviousChatMessagesIfNotAllLoaded(chatId) {
let lowestMessageIdOrNull
const chat = this.state.chats.items[chatId]
if (
!this.isChatNew(chat)
&&
(lowestMessageIdOrNull = (chat.messages.order.length && firstOfArrayAble(chat.messages).id) || null)
&&
lowestMessageIdOrNull != chat.first_message_id
) {
this.setState({
isCurrentChatLoading: true
}, () => {
this.loadPreviousChatMessages(chat.id, lowestMessageIdOrNull)
})
}
}
handleLoadPreviousChatMessages(chatId) {
this.loadPreviousChatMessagesIfNotAllLoaded(chatId)
}
// ...
render() {
const currentChat = this.state.chats.items[this.state.currentChatId] || null
const err = this.state.err
return (
<div className="bl-order-chat-app">
<BlOrderChatBox currentUser={this.currentUser}
chats={arrayAbleItemsOrderToArray(this.state.chats)}
currentChat={currentChat}
isCurrentChatLoading={this.state.isCurrentChatLoading}
onLoadPreviousChatMessages={this.handleLoadPreviousChatMessages}
err={err} />
</div>
)
}
}
I tried to remove all the irrelevant code to simplify the reading. Also here is the file which contains the chatSelector function (normalizes the chat array-able object) and the *ArrayAble* functions (an array-able object to me is basically an object which maps objects through their ids in items and has an order property which keeps the sort):
import { isUndefined, unshiftArray, findIndex } from "../utils";
export function chatSelector(chat, currentUser) {
const newChat = { ...chat }
newChat.messages = arrayAbleItemsOrderToArray(chat.messages).sort((a, b) => {
const sortByUnixTs = a.sent_unix_ts - b.sent_unix_ts
if (sortByUnixTs == 0) {
return a.id - b.id
}
return sortByUnixTs
})
newChat.users = arrayAbleItemsOrderToArray(chat.users).filter(user => user.id != currentUser.id)
return newChat
}
/**
* Given an array-able object, returns its array representation using an order property.
* This function acts as a selector function.
*
* The array-able object MUST have the following shape:
*
* {
* items: {},
* order: []
* }
*
* Where "items" is the object containing the elements of the array mapped by values found in "order"
* in order.
*
* #see https://medium.com/javascript-in-plain-english/https-medium-com-javascript-in-plain-english-why-you-should-use-an-object-not-an-array-for-lists-bee4a1fbc8bd
* #see https://medium.com/#antonytuft/maybe-you-would-do-something-like-this-a1ab7f436808
*
* #param {Object} obj An object.
* #param {Object} obj.items The items of the object mapped by keys.
* #param {Array} obj.order The ordered keys.
* #return {Array} The ordered array representation of the given object.
*/
export function arrayAbleItemsOrderToArray(obj) {
const ret = []
for (const key of obj.order) {
if (!isUndefined(obj.items[key])) {
ret[ret.length] = obj.items[key]
}
}
return ret
}
export function arrayToArrayAbleItemsOrder(array, keyProp = "id") {
const obj = newEmptyArrayAble()
for (const elem of array) {
const key = elem[keyProp]
obj.items[key] = elem
obj.order[obj.order.length] = key
}
return obj
}
export function newEmptyArrayAble() {
return {
items: {},
order: []
}
}
export function isEmptyArrayAble(arrayAbleObj) {
return !arrayAbleObj.order.length
}
export function mergeArrayAbles(arrayAbleObj1, arrayAbleObj2, prependObj2 = false) {
const obj = newEmptyArrayAble()
for (const key of arrayAbleObj1.order) {
if (isUndefined(arrayAbleObj1.items[key])) {
continue
}
obj.items[key] = arrayAbleObj1.items[key]
obj.order[obj.order.length] = key
}
for (const key of arrayAbleObj2.order) {
if (isUndefined(arrayAbleObj2.items[key])) {
continue
}
if (!(key in obj.items)) {
if (!prependObj2) {
// Default.
obj.order[obj.order.length] = key
}
else {
unshiftArray(obj.order, key)
}
}
obj.items[key] = arrayAbleObj2.items[key]
}
return obj
}
export function newArrayAble(initialItem = void 0, keyProp = "id") {
const arrayAble = newEmptyArrayAble()
if (initialItem) {
arrayAble.items[initialItem[keyProp]] = initialItem
arrayAble.order[arrayAble.order.length] = initialItem[keyProp]
}
return arrayAble
}
export function lastOfArrayAble(obj) {
return (
(
obj.order.length
&&
obj.items[obj.order[obj.order.length - 1]]
)
||
void 0
)
}
Thank you for your help. If there's something missing which I should have included, please, let me know!
UPDATE: Thanks to Sultan H. it has improved, though the scroll still blocks as soon as I get the reply from the server. See it here: https://streamable.com/3nzu0
Any idea on how to improve this behaviour further?
Thanks!

Here is an attempt to resolve the performance issue, it's not preferrable to do tasks inside the Arrow Function that calculates the new state, in this case, at loadPreviousChatMessages you are calculating stuff in the callback, which may yeild to a load while setting the state on that context.
Preferrable Changes, replace this.setState inside your function with this code, all I've done here is clear the context by moving all the tasks out:
const chat = this.state.chats.items[chatId];
const messages = arrayToArrayAbleItemsOrder(json.messages);
const newChat = {
...chat,
messages: mergeArrayAbles(messages, chat.messages);
}
const chats = mergeArrayAbles(prevState.chats, newArrayAble(newChat));
const newState = {
...(
makeChatIdCurrent ?
{
currentChatId: chatId,
focusSendMessageTextarea: true,
}
:
{
currentChatId: this.state.currentChatId,
}
),
chats,
isCurrentChatLoading: false,
};
this.setState(() => newState);
If that doesn't entirely solve the issue, can you tell if there was at least an improvment?