Javascript

As React apps grow, managing shared and app-wide state can become challenging. Dedicated state management libraries help tackle these complexities. Let’s compare popular options: Redux Redux uses a centralized store for state: // Store with root reducer const store = createStore(rootReducer); // Dispatch actions store.dispatch(addTodo(text)); // Selectors const todos = useSelector(state => state.todos); Redux enforces unidirectional data flow inspired by functional programming. MobX MobX uses observable variables that update reactively:...

React excels at building fast, dynamic frontends. Node.js shines for server-side APIs and microservices. Together, they make a powerful stack for full stack apps. Let’s walk through integrating React with Node.js: Serving React Builds Use Node.js middleware like Express to serve the React app: // server.js app.use(express.static(path.join(__dirname, 'client/build'))); app.get('*', (req, res) => { res.sendFile(path.join(__dirname, 'client/build', 'index.html)); }); This serves the React build from the /build folder. Proxying API Requests Proxy frontend requests to the backend API:...

As with any framework, React comes with its own set of best practices and optimal patterns. Let’s explore some tips for writing robust React code: Modular Components Break components into reusable, composable units: // Bad function App() { return ( <header> <nav> <logo> <links> </nav> <h1>Welcome!</h1> <footer> <copyright> </footer> </header> ); } // Good function Nav() { return ( <nav> <Logo /> <Links /> </nav> ); } function Header() { return ( <header> <Nav /> <h1>Welcome!...

Bugs are inevitable in complex React applications. Thankfully, React provides great tools to squash bugs quickly. Let’s look at some key techniques for debugging React apps: React Developer Tools The React DevTools Chrome extension lets you inspect React component hierarchies, props, state and more in Chrome: DevTools: <App> <Navbar /> <Profile name="Jane" imageUrl="https://..." /> </App> This provides invaluable visibility into React apps. Error Boundaries Error boundaries catch errors and display fallbacks:...

As React apps scale, you’ll want to structure components for greater reusability and composability. Here are some powerful React patterns: Compound Components The compound components pattern creates component APIs with shared context: // Parent exposes context through 'Box' component function Layout({children}) { return <Box>{children}</Box> } // Children access shared context via Box function Profile() { return ( <Layout> <Box p={2}> <h1>Jane Doe</h1> </Box> </Layout> ); } This provides more flexible APIs than just props....

Animation brings interfaces to life. Thankfully, React has great open source libraries for animation. Let’s compare some popular options: Framer Motion Framer Motion uses declarative props for animation: import { motion } from 'framer-motion'; const boxVariants = { hidden: { opacity: 0 }, visible: { opacity: 1 }, } function MyComponent() { return ( <motion.div initial="hidden" animate="visible" variants={boxVariants} /> ); } Framer Motion allows CSS, SVG, gesture, and physics animations....

Testing is crucial for ensuring React apps are stable and bug-free. Popular tools like Jest and React Testing Library make testing React components simple. Let’s look at how to write great tests for React: render Component Render the component into a test environment using render from React Testing Library: import { render } from '@testing-library/react'; import Button from './Button'; test('displays button text', () => { const { getByText } = render(<Button>Click</Button>); expect(getByText('Click'))....

Fetching data in React often means using stale state and complex caching logic. React Query simplifies data fetching with powerful features like automatic caching, deduplication, and background updates. Let’s explore some key features of React Query: Declarative Data Fetching Fetch data with the useQuery hook: import { useQuery } from 'react-query'; function MyComponent() { const { data, error, isLoading } = useQuery('posts', fetchPosts); // use data } useQuery handles declaring cache keys, performing fetches, and more....

Forms are a common need for many React apps. However, managing form state and validation can be tricky. Thankfully, React provides great libraries to simplify complex forms. Let’s explore some helpful tools: Formik for Form State Formik handles common form tasks: import { Formik } from 'formik'; const MyForm = () => ( <Formik initialValues={{ email: '' }} onSubmit={values => console.log(values)} > {formik => ( <form onSubmit={formik.handleSubmit}> <input name="email" onChange={formik.handleChange} value={formik....

As React apps grow, you may notice performance starting to lag - sluggish interactions, choppy animations, janky scrolling. Luckily, there are many great techniques to optimize React app performance. Let’s look at some top tips: Use React.memo for Component Memoization The React.memo API can memoize component outputs: const MyComponent = React.memo(function MyComponent(props) { /* only rerenders if props change */ }); This prevents unnecessary re-renders if props stay the same....