Q171. How to prevent unnecessary updates using setState?
You can compare the current value of the state with an existing state value and decide whether to rerender the page or not. If the values are the same then you need to re...
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Q172. How do you render Array, Strings and Numbers in React 16 Version?
**Note:** This question references React 16. These features remain valid in current React versions (18/19). **Arrays**: Starting with React 16, you can return multiple si...
Q173. What are hooks?
Hooks is a special JavaScript function that allows you use state and other React features without writing a class. This pattern has been introduced as a new feature in Re...
Q174. What rules need to be followed for hooks?
You need to follow two rules in order to use hooks, 1. **Call Hooks only at the top level of your react functions:** You should always use hooks at the top level of react...
Q175. How to ensure hooks followed the rules in your project?
React team released an ESLint plugin called **eslint-plugin-react-hooks** that enforces Hook's two rules. It is part of Hooks API. You can add this plugin to your project...
Q176. What are the differences between Flux and Redux?
The biggest conceptual difference is the data flow itself: ``` Flux: View ↓ Action ↓ Dispatcher ↓ Multiple Stores ↓ View ``` versus: ``` Redux: View ↓ Action ↓ Middleware...
Q177. What are the benefits of React Router V4?
Below are the main benefits of React Router V4 module, 1. In React Router v4(version 4), the API is completely about components. A router can be visualized as a single co...
Q178. Can you describe about componentDidCatch lifecycle method signature?
The **componentDidCatch** lifecycle method is invoked after an error has been thrown by a descendant component. The method receives two parameters, 1. error: - The error ...
Q179. In which scenarios do error boundaries not catch errors?
Below are the cases in which error boundaries don't work, 1. Inside Event handlers 2. Asynchronous code using **setTimeout or requestAnimationFrame** callbacks 3. During ...
Q180. What is the behavior of uncaught errors in react 16?
**Note:** This behavior was introduced in React 16 and continues in React 18/19. In React 16+, errors that are not caught by any error boundary will result in unmounting ...