Aug 15, 2026· 5 min read
JSX Errors: Unexpected Token, Invalid Children, and Other Fixes
JSX errors are terse but consistent. Learn what unexpected token and invalid children mean, plus the fixes for the most common JSX syntax mistakes.
React
React
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Aug 15, 2026· 5 min read
React Components Explained: Functions, Inputs, and UI
React components are JavaScript functions that turn inputs called props into reusable UI. Learn how function components work and how to compose them.
React
Aug 15, 2026· 5 min read
How to Pass Props in React
Props let a parent component pass data down to its children. Learn how to pass props in React, read them with destructuring, and set default values.
React
Aug 15, 2026· 5 min read
Lifting State Up in React: A Step-by-Step Example
Lifting state up moves shared state to a common parent. Follow a step-by-step example to share one value between two React components.
React
Aug 15, 2026· 5 min read
How to Control a Child Component from Its Parent in React
A parent controls a child component by owning its value and passing it down as props. Learn the controlled component pattern in React.
React
Aug 15, 2026· 5 min read
Why Your React Component Re-renders and How to Trace It
A component re-renders when its state changes or a parent re-renders. Learn the causes and trace them with the React DevTools Profiler.
React
Aug 15, 2026· 5 min read
How to Type React Props with TypeScript
Type React props with an interface or type alias. Learn inline types, optional props, and union types for TypeScript components.
React
Aug 15, 2026· 5 min read
React.ComponentProps Explained: Reuse Existing Component Types
React.ComponentProps extracts the props type of an element or component. Learn to reuse and extend existing prop types instead of rewriting them.
React
Aug 15, 2026· 5 min read
How to Build Polymorphic React Components with TypeScript
Build polymorphic React components that render as any element with an as prop. Type the pattern with ElementType and generics in TypeScript.
React
Aug 15, 2026· 5 min read
How to Update Objects in React State
Update objects in React state by replacing them with new copies instead of mutating. Use the spread syntax for flat fields and nested updates.
React
Aug 15, 2026· 5 min read
How React Batches State Updates
React batches state updates by waiting for an event handler to finish, then applying every change in one re-render. See how batching works.
React
Aug 15, 2026· 6 min read
How to Combine useReducer and Context
Combine useReducer with context to share reducer state and dispatch down the tree without prop drilling, using a provider and small custom hooks.
ContextReactusereducer