Develop Reference

React Virtualized use recomputeRowHeights Method in functional components

Might be a silly question but I am trying to use the public method recomputeRowHeights specified in the documentation in a functional component while the entire react-virtualized library is based on class components.
My code for using it will be the following. It recomputes all row heights after window resizes.
window.addEventListener('resize', function(event) {
recomputeRowHeights();
console.log("recomputed!")
}, true);
Here is my wrapper for the List component:
import React from "react";
import { useState, useRef } from "react";
import { InfiniteLoader, List, WindowScroller } from 'react-virtualized';
import AutoSizer from 'react-virtualized-auto-sizer';
import Loader from "../components/decroations/Loader";
import TopMargin from "../components/decroations/TopMargin";
export default function InfiniteScroll({ getNextList, preRenderRadius }) {
const [hasNextPage, setHasNextPage] = useState(true);
const [isNextPageLoading, setIsNextPageLoading] = useState(false);
const [list, setList] = useState([{Component: <TopMargin />, height: 0.05}]);
const rowCount = hasNextPage ? list.length + 1 : list.length;
const loadMoreRows = isNextPageLoading ? () => {} : loadNextPage;
const isRowLoaded = ({index}) => !hasNextPage || index < list.length;
function rowheight({ index }){
if (!isRowLoaded({index})){
return 0.8*window.innerWidth;
}else{
return list[index].height*window.innerWidth;
}
}
const Item = ({index, key, style}) => {
if (!isRowLoaded({index})) {
return (
<div key={key} style={style} className='loaderWrapper'>
<Loader/>
</div>
)
} else {
return(
<div key={key} style={style}>
{list[index].Component}
</div>
)
};
}
function loadNextPage(){
setIsNextPageLoading(true);
getNextList(list.length - 1).then((newRows) => {
setList(list.concat(newRows))
setIsNextPageLoading(false)
}).catch(()=>{
setHasNextPage(false)
})}
return (
<InfiniteLoader
isRowLoaded={isRowLoaded}
loadMoreRows={loadMoreRows}
rowCount={rowCount}
threshold={preRenderRadius}
>
{({ onRowsRendered, registerChild }) => (
<WindowScroller>
{({ height, isScrolling, scrollTop }) => (
<AutoSizer disableHeight>
{({width}) => (
<List
autoHeight
height={height}
onRowsRendered={onRowsRendered}
ref={registerChild}
rowCount={rowCount}
rowHeight={rowheight}
rowRenderer={Item}
width={width}
isScrolling={isScrolling}
scrollTop={scrollTop}
/>
)}
</AutoSizer>)}
</WindowScroller>
)}
</InfiniteLoader>
);
}

Why is my ref always null even though I'm setting it to a component

So basically I have 2 pieces, the sidebar, then the opener. I'm trying to setup a ref that will connect the sidebar to the current opener. The opener is a functional component, and no matter what I do the current value is null. Am I missing something? I'm just trying to resize a component. My goal is to be able to resize the shown sidebar with the opener.
Here's part of the Render function.
render() {
const { selected, isSidebar, selectedType, search, active } = this.state;
const { pending, callback, resource } = this.props;
const pendingLengh = pending ? pending.length : 0;
const callbackLength = callback ? callback.length : 0;
const isResource = !resource || !Object.keys(resource).length;
return (
<div className="newPatientPage mainPage">
{this.renderMetadata()}
<SubTopBar
title="New Patient Processing"
noLeftSide={true}
subStatus={this.getStatus(pendingLengh, callbackLength)}
isBarcode={!isResource}
sideComponent={this.renderSideComponent()}
/>
{
active ?
<SnapshotSideBar
ref={this.sidebarRef}
patientResource={this.props.patientResource}
isShow={isSidebar}
settup={this.state.settup}
isScan={true}
handleCloseSidebar={this.handleCloseSidebar}
/> :
<NewPatientSideBar
ref={this.sidebarRef}
stepProps={this.state.stepProps}
selected={selected}
isShow={isSidebar}
handleCloseSidebar={this.handleCloseSidebar}
/>
}
<SidebarExtension sidebarToggle={this.toggleSidebar} sidebarReference={this.sidebarRef} sidebarState={isSidebar}/>
Here's the SidebarExtension component
const SidebarExtension = ({
sidebarToggle,
sidebarReference,
sidebarState,
...restProps
}) => {
const [xPos, setXPos] = useState(0);
const [width, setWidth] = useState();
const [openerPosition, setOpenerPosition] = useState(50);
const [isOpen, setIsOpen] = useState(false);
const toggleSidebar = () => {
sidebarToggle();
setIsOpen(!isOpen);
};
useEffect(() => {
setIsOpen(sidebarState);
}, [sidebarState])
if ((!isOpen && !sidebarState)) {
return (
<>
<div
className="resizeHandle"
style={{
right: "0Px",
}}
onClick={toggleSidebar}
>
<LeftCharvenSVG />
</div>
</>
);
}
return (
<>
<div
className="resizeHandle active"
onClick={toggleSidebar}
onMouseDown={startResize}
>
<LeftCharvenSVG />
</div>
</>
);
};
export default SidebarExtension;
Here's what the constructor looks like.
Main Constructor

From the docs https://reactjs.org/docs/forwarding-refs.html you need to wrap your functional component in React.forwardRef()
Example
const FancyButton = React.forwardRef((props, ref) => (
<button ref={ref} className="FancyButton">
{props.children}
</button>
));
// You can now get a ref directly to the DOM button:
const ref = React.createRef();
<FancyButton ref={ref}>Click me!</FancyButton>;
In your case that would be:
const SidebarExtension = React.forwardRef(({
sidebarToggle,
sidebarReference,
sidebarState,
...restProps
}, ref) => {
const [xPos, setXPos] = useState(0);
const [width, setWidth] = useState();
const [openerPosition, setOpenerPosition] = useState(50);
const [isOpen, setIsOpen] = useState(false);
const toggleSidebar = () => {
sidebarToggle();
setIsOpen(!isOpen);
};
useEffect(() => {
setIsOpen(sidebarState);
}, [sidebarState])
if ((!isOpen && !sidebarState)) {
return (
<>
<div
className="resizeHandle"
style={{
right: "0Px",
}}
ref={ref}
onClick={toggleSidebar}
>
<LeftCharvenSVG />
</div>
</>
);
}
return (
<>
<div
className="resizeHandle active"
onClick={toggleSidebar}
onMouseDown={startResize}
>
<LeftCharvenSVG />
</div>
</>
);
});
export default SidebarExtension;

State not updating in different component

I have a searchbar component that I used context to import into another component. The state of the searchbar in its own component works but when I use the context to import it to another component it does not work. I have used other contexts in my project and they have worked but the searchbar state doesn't. I have no idea where to start, or how to go about fixing it. Can someone point me in the right direction?
export const SearchInput = () => {
const [searchInput, setSearchInput] = useState('');
const handleSubmit = (e) => {
e.preventDefault()
}
return (
<div>
<form onSubmit={handleSubmit}>
<input type='text'
className='search-input'
name='search-movies'
value={searchInput}
onChange={(e) => setSearchInput(e.target.value)} />
</form>
</div>
)
}
//Use Context Component
export const SearchContext = React.createContext()
export function SearchProvider({ children }) {
const [searchInput, setSearchInput] = useState('');
const value = {
searchInput
}
return (
<div>
<SearchContext.Provider value={value}>
{children}
</SearchContext.Provider>
</div>
)
}
const Movies = () => {
const { data, loading, isErr } = useFetch([
`https://api.themoviedb.org/3/list/7077601?api_key=${process.env.REACT_APP_API_KEY}&language=en-US`,
`https://api.themoviedb.org/3/list/7078334?api_key=${process.env.REACT_APP_API_KEY}&language=en-US`,
`https://api.themoviedb.org/3/list/7078244?api_key=${process.env.REACT_APP_API_KEY}&language=en-US`
]);
const { watchList, handleClick } = useContext(WatchListContext);
const { searchInput } = useContext(SearchContext)
const [moviePoster, setmoviePoster] = useState(`giphy (1).gif`);
const [movieTitle, setmovieTitle] = useState('');
const [movieDescription, setmovieDescription] = useState('')
const styles = {
backgroundImage: `url(${moviePoster})`
};
SwiperCore.use([Navigation, Pagination, Scrollbar, A11y]);
return (
<div className='movie-container'>
{isErr && <div className="error">{isErr}</div>}
{loading && <Spinner animation="border" variant="secondary" className="spinner" >
<span>Loading...</span>
</Spinner>}
<div className='movie-hero' style={styles}></div>
<div className="contains-descriptions">
<h2 className="hero-movie-title show-movie">{movieTitle}</h2>
<p className="hero-movie-description show-movie">{movieDescription}</p>
</div>
<section className="movies">
<h2 style={{ color: 'white', marginLeft: '20px' }}>Action </h2>
{data && <Swiper
spaceBetween={10}
slidesPerView={6}
pagination={{ clickable: true }}
scrollbar={{ draggable: true }}
onSlideChange={() => console.log('slide change')}
onSwiper={(swiper) => console.log(swiper)}
>
{data && data[0].items.map(movie =>
<SwiperSlide key={movie.id}>
<div className='movie' >
<img onMouseOver={() => {
setmoviePoster(`${"https://image.tmdb.org/t/p/original" + movie.poster_path}`);
setmovieTitle(movie.original_title);
setmovieDescription(movie.overview);
}}
src={'https://image.tmdb.org/t/p/original' + movie.poster_path} width='250' height='300'
alt='Promotional Poster For Movie'
/>
<button className="watchlist-btn"
onClick={() => handleClick(movie.original_title)}>
{watchList.includes(movie.original_title) ?
<i className="fas fa-minus-circle"></i> :
<i className="fas fa-plus-circle"></i>}
</button>
</div>
</SwiperSlide>
)
}
</Swiper>}
</section>

I'm assuming a component tree that looks something like this:
+-- SearchProvider
| +-- SearchInput
| +-- Movies
Your SearchProvider should be providing both the state and the state setter as its value:
export const SearchContext = React.createContext()
export function SearchProvider({ children }) {
const [searchInput, setSearchInput] = useState('');
const value = {
searchInput,
setSearchInput
};
return ...
}
Your SearchInput should no longer be controlling its own local state. That state now has to be shared with the rest of the tree. Instead, it subscribes to the context and updates it directly:
export const SearchInput = () => {
const { searchInput, setSearchInput } = React.useContext(SearchContext);
const handleSubmit = (e) => {
e.preventDefault()
};
return ...
}

Why are you using context and not just useState and props?
I think it would work with something like the following:
export const SearchInput = (props) => {
const handleSubmit = (e) => {
e.preventDefault()
}
return (
<div>
<form onSubmit={handleSubmit}>
<input type='text'
className='search-input'
name='search-movies'
value={props.value}
onChange={(e) => props.onChange(e.target.value)} />
</form>
{props.children}
</div>
)
}
export function SearchCompoent({ children }) {
const [searchInputValue, setSearchInputValue] = useState('');
return (
<SearchInput value={searchInputValue}>
{children}
</SearchInput>
)
}

How to pass data to {props.children}

On my follow up question from here : How to pass data from child to parent component using react hooks
I have another issue.
Below is the component structure
export const Parent: React.FC<Props> = (props) => {
const [disabled, setDisabled] = React.useState(false);
const createContent = (): JSX.Element => {
return (
<Authorization>
{<ErrorPanel message={errorMessage} setDisabled={setDisabled}/>}
<MyChildComponent/>
</<Authorization>
);
}
return (
<Button onClick={onSubmit} disabled={disabled}>My Button</Button>
{createContent()}
);
};
const Authorization: React.FC<Props> = (props) => {
const [disabled, setDisabled] = React.useState(false);
const render = (errorMessage : JSX.Element): JSX.Element => {
return (
<>
{<ErrorPanel message={errorMessage} setDisabled={setDisabled}/>}
</>
);
};
return (
<>
<PageLoader
queryResult={apiQuery}
renderPage={render}
/>
{props.children}
</>
);
};
How do I pass the disabled state value from Authorization component to my child which is invoked by
{props.children}
I tried React.cloneElement & React.createContext but I'm not able to get the value disabled to the MyChildComponent. I could see the value for disabled as true once the errorMessage is set through the ErrorPanel in the Authorization component.
Do I need to have React.useEffect in the Authorization Component?
What am I missing here?

You need to use React.Children API with React.cloneElement:
const Authorization = ({ children }) => {
const [disabled, setDisabled] = React.useState(false);
const render = (errorMessage) => {
return (
<>{<ErrorPanel message={errorMessage} setDisabled={setDisabled} />}</>
);
};
return (
<>
<PageLoader queryResult={apiQuery} renderPage={render} />
{React.Children.map(children, (child) =>
React.cloneElement(child, { disabled })
)}
</>
);
};
// |
// v
// It will inject `disabled` prop to every component's child:
<>
<ErrorPanel
disabled={disabled}
message={errorMessage}
setDisabled={setDisabled}
/>
<MyChildComponent disabled={disabled} />
</>

You can make use of React.cloneElement to React.Children.map to pass on the disabled prop to the immediate children components
const Authorization: React.FC<Props> = (props) => {
const [disabled, setDisabled] = React.useState(false);
const render = (errorMessage : JSX.Element): JSX.Element => {
return (
<>
{<ErrorPanel message={errorMessage} setDisabled={setDisabled}/>}
</>
);
};
return (
<>
<PageLoader
queryResult={apiQuery}
renderPage={render}
/>
{React.Children.map(props.children, child => {
return React.cloneElement(child, { disabled })
})}
</>
);
};
UPDATE:
Since you wish to update the parent state to, you should store the state and parent and update it there itself, instead of storing the state in child component too.
export const Parent: React.FC<Props> = (props) => {
const [disabled, setDisabled] = React.useState(false);
const createContent = (): JSX.Element => {
return (
<Authorization setDisabled={setDisabled}>
{<ErrorPanel message={errorMessage} disabled={disabled} setDisabled={setDisabled}/>}
<MyChildComponent disabled={disabled}/>
</<Authorization>
);
}
return (
<Button onClick={onSubmit} disabled={disabled}>My Button</Button>
{createContent()}
);
};
const Authorization: React.FC<Props> = (props) => {
const render = (errorMessage : JSX.Element): JSX.Element => {
return (
<>
{<ErrorPanel message={errorMessage} disabled={props.disabled} setDisabled={props.setDisabled}/>}
</>
);
};
return (
<>
<PageLoader
queryResult={apiQuery}
renderPage={render}
/>
{props.children}
</>
);
};

How to pass prop to component's children

const ListView = () => {
return(
<ul>
<ListItem modal={<Modal />} />
</ul>
)
};
const ListItem = (props) => {
const [visible, setVisible] = useState(false);
const toggle = () => setVisible(!visible)
return (
<>
<li>
ListItem
</li>
<ModalWrapper toggle={toggle}>{props.modal}</ModalWrapper>
</>
)
}
const ModalWrapper = (props) => {
if(!props.visible) return null;
return (
<>
{props.children}
</>
)
}
const Modal = ({ toggle }) => {
/* I would like to use toggle() here. */
return (
<>
<div onClick={toggle} className="dimmer"></div>
<div className="modal">modal</div>
</>
)
}
I have a function toggle() in <ListItem /> as shown above.
I am struggling to use toggle() in <Modal />.
Is it possible or are there any suggestions?

You need to inject toggle to ModalWrapper children, be careful not to override toggle prop on Modal after it.
const ModalWrapper = ({ children, visible, toggle }) => {
const injected = React.Children.map(children, child =>
React.cloneElement(child, { toggle })
);
return <>{visible && injected}</>;
};
Refer to React.cloneElement and React.Children.map.
Demo: