Calling setState() with a function but not using previous state
Calling setState() with a function but not using the previous state in React can lead to inconsistent or incorrect UI updates, especially when the new state depends on the current….
Tag: React troubleshooting
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….
Mutating props inside a child component
Mutating props inside a child component in React is a common mistake that can lead to unpredictable behavior, bugs, and issues with React’s unidirectional data flow. Props are meant to….
Setting state inside render() leading to infinite loop
Avoiding Infinite Loops from State Updates in Render A critical React mistake is calling state update functions (like setState or state setters from useState) inside the render() method or function….
Modifying state directly instead of using setState()
Proper State Management in React Components A critical React anti-pattern is modifying state directly rather than using the proper state update methods. Here’s how to handle state correctly in both….
Accessing state before super(props) in a class component
Understanding super(props) and State Initialization in Class Components A common React anti-pattern is trying to access this.state before calling super(props) in a class component constructor. Here’s what you need to….
Passing a function instead of calling it in event handlers (onClick={handleClick()} instead of onClick={handleClick})
Correct Function Handling in React Event Handlers A common React mistake is incorrectly passing functions to event handlers, which can cause immediate execution or other unexpected behavior. Here’s how to….
Forgetting parentheses when returning JSX inside an arrow function
Handling JSX Return in Arrow Functions A common mistake when using arrow functions in React is forgetting parentheses when returning JSX, which can lead to unexpected behavior or syntax errors…..
Assigning a variable inside JSX without using curly braces
Correct Variable Usage in JSX In JSX, you can’t directly assign variables or execute statements without wrapping them in curly braces {}. Here’s how to properly handle variable assignment and….
Forgetting to import React when using JSX (React 17+ solves this)
The Classic Problem (Pre-React 17) Before React 17, you needed to import React in every file using JSX because JSX was transformed into React.createElement() calls: Without this import, you’d get….