Q821. What happens if you call `useState` conditionally?
As per rules of React Hooks, hooks must be called unconditionally. For example, if you conditionally call it: ```js if (someCondition) { const [state, setState] = useStat...
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 (1,236 available).
Active:
Difficulty: easy ×
Q822. How do you perform form validation using javascript?
JavaScript can be used to perform HTML form validation. For example, if the form field is empty, the function needs to notify, and return false, to prevent the form being...
Q823. Is useState Synchronous or Asynchronous?
The `useState` hook is synchronous, but state updates are asynchronous. When you call `useState()`, it runs synchronously and returns the state variable and setter functi...
Q824. How do you perform form validation without javascript?
You can perform HTML form validation automatically without using javascript. The validation enabled by applying the `required` attribute to prevent form submission when t...
Q825. Can you explain how useState works internally?
React’s hooks, including `useState`, rely on some internal machinery that keeps track of state **per component** and **per hook call** during rendering. Here's a simplifi...
Q826. What are the DOM methods available for constraint validation?
The below DOM methods are available for constraint validation on an invalid input, 1. `checkValidity()`: It returns true if an input element contains valid data. 2. `setC...
Q827. What is `useReducer`? Why do you use useReducer?
The `useReducer` hook is a React hook used to manage **complex state logic** inside **functional components**. It is conceptually similar to **Redux**. i.e, Instead of di...
Q828. Explain the //, %, and ** operators in Python?
The // operator performs floor division. It will return the integer part of the result on division. ```python >>> 7//2 ``` 3 Normal division would return 3.5 here. Simila...
Q829. What are the available constraint validation DOM properties?
Below are the list of some of the constraint validation DOM properties available, 1. `validity`: It provides a list of boolean properties related to the validity of an in...
Q830. How does `useReducer` works? Explain with an example
The `useReducer` hooks works similarly to Redux, where: * You define a **reducer function** to handle state transitions. * You dispatch actions to update the state. **Cou...