ReactJS Advanced Interview Questions: Get Hired in 2024

Introduction

Landing a job as a React developer requires a solid understanding of its advanced concepts. This blog post aims to equip you with the knowledge to confidently tackle advanced ReactJS interview questions.

Key Features of React

• Component-Based Architecture: React promotes building UI components, making code modular and reusable.

• Declarative Syntax: You describe how the UI should look, and React handles the updates.

• Virtual DOM: React uses a virtual representation of the DOM, optimizing performance.

• JSX: A syntax extension that makes writing HTML-like structures within JavaScript more intuitive.

What is JSX?

JSX is a syntax extension for JavaScript that allows you to write HTML-like structures directly in your JavaScript code. It's compiled into regular JavaScript before execution.

Can Web Browsers Read JSX Directly?

No, web browsers cannot directly understand JSX. It needs to be transpiled into regular JavaScript using tools like Babel.

What is the Virtual DOM?

The virtual DOM is a lightweight, in-memory representation of the actual DOM. React uses it to efficiently update the UI by only updating the necessary parts.

Why Use React Instead of Other Frameworks, Like Angular?

React offers several advantages:

• Component-Based: It's easier to manage and reuse code.

• Flexibility: You can integrate React into existing projects.

• Performance: The virtual DOM optimizes updates.

• Large Community: A vast ecosystem of tools and resources.

What is the Difference Between the ES6 and ES5 Standards?

ES6 (ECMAScript 6) introduced significant improvements over ES5, including:

• Arrow Functions: A concise syntax for defining functions.

• Classes: A more object-oriented approach to creating objects.

• Modules: A mechanism for organizing and reusing code.

• Template Literals: A way to create multi-line strings and interpolate expressions.

How Do You Create a React App?

You can create a React app using the Create React App (CRA) tool:

Bash

npx create-react-app my-app

What is an Event in React?

In React, events are user interactions with components, such as clicks, key presses, or form submissions.

How Do You Create an Event in React?

You attach event handlers to elements using JSX syntax. For example:

JavaScript

<button onClick={handleClick}>Click me</button>

What are Synthetic Events in React?

Synthetic events are cross-browser abstractions of native browser events. They provide a consistent interface across different browsers.

Conclusion

By mastering these advanced ReactJS concepts, you'll be well-prepared to tackle challenging interview questions and excel as a React developer.

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