Q101. What are the restrictions of web workers on DOM?
WebWorkers don't have access to below javascript objects since they are defined in an external files 1. Window object 2. Document object 3. Parent object
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 (1,100 available).
Active:
Tag: javascript ×
Q102. What is a switching component?
A _switching component_ is a component that renders one of many components. We need to use object to map prop values to components. For example, a switching component to ...
Q103. What is a promise?
A **Promise** is a JavaScript object that represents the eventual completion (or failure) of an asynchronous operation and its resulting value. It acts as a placeholder f...
Q104. What are the Pointer Events supported in React?
_Pointer Events_ provide a unified way of handling all input events. In the old days we had a mouse and respective event listeners to handle them but nowadays we have man...
Q105. Why do you need a promise?
Promises are **used to handle asynchronous operations**, especially in languages like JavaScript, which often work with non-blocking operations such as network requests, ...
Q106. Why should component names start with capital letter?
If you are rendering your component using JSX, the name of that component has to begin with a capital letter otherwise React will throw an error as an unrecognized tag. T...
Q107. Explain the three states of promise?
Promises have three states: 1. **Pending:** This is an initial state of the Promise before an operation begins 2. **Fulfilled:** This state indicates that the specified o...
Q108. Are custom DOM attributes supported in React v16?
**Note:** This question references React v16, which is outdated. The information below applies to React 16+, including current versions (React 18/19). Yes. Starting with ...
Q109. What is a callback function?
A callback function is a function passed into another function as an argument. This function is invoked inside the outer function to complete an action. Let's take a simp...
Q110. How to loop inside JSX?
You can simply use `Array.prototype.map` with ES6 _arrow function_ syntax. For example, the `items` array of objects is mapped into an array of components: ```jsx harmony...