Something to do with routes in index.js and routes in app.js

well-written

React 组件更新机制 tip 1

Um Hook em React Native é uma função que permite que um componente funcional tenha um estado interno e execute efeitos colaterais, sem a necessidade de criar componentes de classe.

O useState é um dos Hooks mais utilizados Ele permite manter um estado local em uma função de um componente funcional. Para usá-lo, declara-se uma variável e uma função de atualização de estado usando o useState Hook

Anti pattern: Initializing state with prop

This is a common example of redundant state

```js

export const loader = async () => {

// fire them all at once<br /> const critical1Promise = fetch('/test?text=critical1&delay=250').then(res => res.json()); const critical2Promise = fetch('/test?text=critical2&delay=500').then(res => res.json()); const lazyResolvedPromise = fetch('/test?text=lazyResolved&delay=100').then(res => res.json()); const lazy1Promise = fetch('/test?text=lazy1&delay=500').then(res => res.json()); const lazy2Promise = fetch('/test?text=lazy2&delay=1500').then(res => res.json()); const lazy3Promise = fetch('/test?text=lazy3&delay=2500').then(res => res.json()); const lazyErrorPromise = fetch('/test?text=lazy3&delay=3000').then(res => { throw Error('Oh noo!') });

// await for the response return defer({ critical1: await critical1Promise, critical2: await critical2Promise, lazyResolved: lazyResolvedPromise, lazy1: lazy1Promise, lazy2: lazy2Promise, lazy3: lazy3Promise, lazyError: lazyErrorPromise }) } ```

React JS is a JavaScript library used to create extensible and adaptable user interfaces. Our React development company team of the best React.js / React developers, software engineers, and programmers in India provides custom React development services that handle data updates and synchronization without page reloading, as well as integration with existing applications or systems.

React JS development services, an extensible and adaptable JavaScript library for creating user interfaces. Our team of the best React.js / React developers, software engineers, and programmers in India provides custom React js development services.

This is a note, actually I'm just testing how well this works

test

Hire React Native Developer to build dynamic Android and iOS apps. Our React Native app developers have hands-on experience in working with different projects.

Chadeau-Hyam, M., Wang, H., Eales, O., Haw, D., Bodinier, B., Whitaker, M., Walters, C. E., Ainslie, K. E. C., Atchison, C., Fronterre, C., Diggle, P. J., Page, A. J., Trotter, A. J., Ashby, D., Barclay, W., Taylor, G., Cooke, G., Ward, H., Darzi, A., … Elliott, P. (2022). SARS-CoV-2 infection and vaccine effectiveness in England (REACT-1): A series of cross-sectional random community surveys. The Lancet Respiratory Medicine, 0(0). https://doi.org/10.1016/S2213-2600(21)00542-7

```js import { useMutation, useQuery, useQueryClient } from 'react-query';

export default function usePersistentContext(key) { const queryClient = useQueryClient();

const { data } = useQuery(key, () => localStorage.getItem(key));

const { mutateAsync: setValue } = useMutation( (value) => localStorage.setItem(key, value), { onMutate: (mutatedData) => { const current = data; queryClient.setQueryData(key, mutatedData); return current; }, onError: (_, __, rollback) => { queryClient.setQueryData(key, rollback); }, } );

return [data, setValue]; } ```

js function SetContext() { const [value, setValue] = usePersistentContext('item_context'); return ( <button onClick={() => setValue(value === 'on' ? 'off' : 'on')}> Click me {value} </button> ); }

change事件更新state，也就是用户输入的value，这就是受控组件

value随用户输入而改变state

createRoot()返回一个ReactDOM对象，该对象具有render方法。

so its not an actual race condition b/w two parallel instructions, but rather just a result of an optimisation performed by react

React Helmet

```js import {Helmet} from "react-helmet";

const Demo = props => ( <br /> <div className="application"> <Helmet> <script src="/path/to/resource.js" type="text/javascript" /> </Helmet> ... </div>

); ```

DOM Method

```js componentDidMount () { const script = document.createElement("script"); script.src = "/path/to/resource.js"; script.async = true; document.body.appendChild(script); }

export const appendScript = (scriptToAppend) => { const script = document.createElement("script"); script.src = scriptToAppend; script.async = true; document.body.appendChild(script); }

class Demo extends React.Component { componentDidMount () { appendScript("/path/to/resource.js"); } } ```

React Hooks

js useEffect(() => { const script = document.createElement('script'); script.src = "/path/to/resource.js"; script.async = true; document.body.appendChild(script); return () => { document.body.removeChild(script); } }, []);

```js import { useEffect } from 'react'; const importScript = resourceUrl=> { useEffect(() => { const script = document.createElement('script'); script.src = resourceUrl; script.async = true; document.body.appendChild(script); return () => { document.body.removeChild(script); } }, [resourceUrl]); };

const Demo = props => { importScript("/path/to/resource.js"); } ```

asdfasdfasdfasdf

Hire ReactJS Developers

Hire React Native Developers

Coronavirus infections remain high while Omicron ‘stealth variant’ rises—REACT | Imperial News | Imperial College London. (n.d.). Imperial News. Retrieved 22 March 2022, from https://www.imperial.ac.uk/news/234517/coronavirus-infections-remain-high-while-omicron/

Clean form code. Pretty elegant + covers best practices. This video also showed me some previously unknown HTML features.

https://www.youtube.com/watch?v=tIdNeoHniEY

js queryClient .getQueryCache() .findAll(['partial', 'key']) .forEach(({ queryKey }) => { queryClient.setQueryData(queryKey, newData) })

Title: React with Typescript Crash Course Published: APR/2021 Source: https://www.youtube.com/watch?v=jrKcJxF0lAU

Dr Duncan Robertson. (2022, January 31). Cases will increase today. The way that cases are counted is changing. A short thread. 🧵 https://coronavirus.data.gov.uk/details/whats-new/record/af008739-ffa3-47b8-8efc-ef109f2cfbdd https://t.co/WY655My1RV [Tweet]. @Dr_D_Robertson. https://twitter.com/Dr_D_Robertson/status/1488115542263271427

It is ok to use url as key for React query

Routen, A., O’Mahoney, L., Ayoubkhani, D., Banerjee, A., Brightling, C., Calvert, M., Chaturvedi, N., Diamond, I., Eggo, R., Elliott, P., Evans, R. A., Haroon, S., Herret, E., O’Hara, M. E., Shafran, R., Stanborough, J., Stephenson, T., Sterne, J., Ward, H., & Khunti, K. (2022). Understanding and tracking the impact of long COVID in the United Kingdom. Nature Medicine, 28(1), 11–15. https://doi.org/10.1038/s41591-021-01591-4