Q421. Why do you not need error boundaries for event handlers?
Error boundaries do not catch errors inside event handlers. React doesn’t need error boundaries to recover from errors in event handlers. Unlike the render method and lif...
Technical Question Bank · Peer-Reviewed
Job Interview Questions and Answers Directory
Search and filter frequently asked interview questions across technical, programming, and behavioral domains. Tailor your interview preparation by difficulty for freshers or experienced developers (454 available).
Active:
Tag: react ×
Q422. What is the difference between try catch block and error boundaries?
Try catch block works with imperative code whereas error boundaries are meant for declarative code to render on the screen. For example, the try catch block used for belo...
Q423. What is the required method to be defined for a class component?
The `render()` method is the only required method in a class component. i.e, All methods other than render method are optional for a class component.
Q424. What are the possible return types of render method?
Below are the list of following types used and return from render method, 1. **React elements:** Elements that instruct React to render a DOM node. It includes html eleme...
Q425. What is the main purpose of constructor?
The constructor is mainly used for two purposes, 1. To initialize local state by assigning object to this.state 2. For binding event handler methods to the instance For e...
Q426. Is it mandatory to define constructor for React component?
No, it is not mandatory. i.e, If you don’t initialize state and you don’t bind methods, you don’t need to implement a constructor for your React component.
Q427. Why should not call setState in componentWillUnmount?
You should not call `setState()` in `componentWillUnmount()` because once a component instance is unmounted, it will never be mounted again.
Q428. What is the purpose of getDerivedStateFromError?
This lifecycle method is invoked after an error has been thrown by a descendant component. It receives the error that was thrown as a parameter and should return a value ...
Q429. What is the methods order when component re-rendered?
An update can be caused by changes to props or state. The below methods are called in the following order when a component is being re-rendered. 1. static getDerivedState...
Q430. What are the methods invoked during error handling?
Below methods are called when there is an error during rendering, in a lifecycle method, or in the constructor of any child component. 1. static getDerivedStateFromError(...