Using key props incorrectly in .map() lists
Using key props incorrectly in .map() operations is a common React anti-pattern that can lead to performance issues, state bugs, and unexpected rendering behavior. Here’s how to properly handle keys….
Tag: React rendering
Passing an object in setState() without creating a new reference
Proper Object State Updates in React When updating state objects in React, it’s crucial to create new object references rather than mutating existing ones. Here’s how to handle object state….
Forgetting to use React Fragments (<>…)
The Importance of React Fragments and How to Use Them Properly A common mistake in React development is forgetting to use Fragments when returning multiple elements, which leads to unnecessary….
Trying to use multiple root elements in JSX without a wrapper
Using Multiple Root Elements in JSX In React/JSX, you normally can’t return multiple root elements from a component because JSX must have a single parent element. However, there are several….
Using an object directly inside JSX instead of JSON.stringify
When you try to render an object directly in JSX, React throws an error because objects aren’t valid as React children. Here’s how to properly display object content in your….
Excessive DOM manipulations inside React components
Optimizing DOM Manipulations in React Components Excessive direct DOM manipulation in React components defeats the purpose of React’s virtual DOM and can lead to performance issues. Here’s how to properly….
Incorrect dependency array in useEffect, causing unexpected behavior
Mastering useEffect Dependency Arrays The dependency array in useEffect is crucial for controlling when your effects run. Getting it wrong can lead to infinite loops, stale data, or effects that….
Calling event handler instead of passing reference – onClick={this.handleClick()} instead of onClick={this.handleClick}
Proper Event Handler Passing in React A common mistake in React is accidentally calling an event handler immediately instead of passing a reference to it. This causes the function to….
Invalid JSX syntax – Adjacent JSX elements must be wrapped in an enclosing tag
The error “Adjacent JSX elements must be wrapped in an enclosing tag” occurs when you try to return multiple JSX elements from a React component without enclosing them in a….
Missing dependencies – ReactDOM is not defined
This error occurs when ReactDOM isn’t properly imported or available in your project. Here’s how to resolve it: Standard Solutions 1. Correct Import Syntax (React 18+) 2. Legacy Import Syntax….