Introduction
The MERN Stack is the most popular web development framework that includes MongoDB, Express, React, and Node.js etc. these technologies provide a complete solution for building well developed web applications. The MERN Stack technology simplifies the development process of applications and is high in demand among the employers. Major companies like Facebook, Instagram, WhatsApp, Dropbox, and Netflix etc use these technologies. To enhance your chances of getting hired by the top companies, it’s important to prepare for the top MERN Stack interview questions.
In this article we will discuss the MERN Stack Interview Questions. These Interview questions will help you to complete your preparation for the full stack Developer role.
MERN Stack Interview questions
1. Who is MERN Stack Developer?
A MERN Stack Developer is the one who builds web applications using MongoDB, Express, React, and Node.js. These technologies create both the front end and back-end, as the user interacts with the front end and at the back-end, handles server-side logic.
2. What is React JS?
ReactJS is the technology mostly used in the JavaScript library for building user interfaces (UIs) in various web applications. It helps developers to create reusable components, making it easier to develop complex UIs. It is known for its efficiency, ReactJS technology uses a virtual DOM to render components quickly and operates on the client side in web browsers. It utilizes a JavaScript extension (JSX), to define UI components.
3. Explain the MVC Architecture.
The Model-View-Controller (MVC) framework organizes code for web applications into three parts which includes Model, View, and Controller. Each part of MVC has a specific role. The MVC framework stores and manages the data properly, presenting it in an understandable format for the application.
4. What are the building blocks of React?
There are five main building blocks of React which are as follows:
- Components: These are pieces of code that generate HTML and can be reused
- JSX: JSX (JavaScript and XML) which enables HTML writing in React.
- Props: Props are the function parameters, while state is the same as variables.
- Context: It enables data to flow through components as props in a hierarchy.
- Virtual DOM: Virtual DOM is a lightweight version of the actual DOM which simplifies DOM manipulation.
5. What is Reconciliation in React?
Reconciliation in React JS is the process of checking whether a component’s props or state changes require an update to the real DOM. React compares the old element with the new one, and if they differ, it updates the DOM accordingly with the new one.
6. What are the pure components in MERN Stack?
In the MERN stack, pure components are similar to standard components but differ by using the shouldComponentUpdate method. Their main role of pure components is to compare props and state whenever there are changes.
7. What is JSX in React JS?
JSX is a syntactic extension for JavaScript that allows full access to JavaScript features. React components use JSX by using JavaScript expressions, placed in curly braces. JSX expressions are converted into standard JavaScript objects after compilation.
8. What are the benefits of using JSX in React?
- Using JSX speeds up performance by converting code into regular JavaScript.
- JSX is type-safe, having better code structure and early error detection during compilation.
- It becomes easy for template writing, especially for those who know HTML.
9. What are forms in React?
React uses forms through which users can interact with web applications. Users can interact with the application through forms, which displays text fields, buttons, checkboxes, and radio buttons used for entering necessary information.
10. What are the techniques to optimize React app performance?
- Using memorization to avoid unnecessary updates.
- Use libraries like react-virtualized.
- Code splitting techniques.
- Use React lazy() and Suspense.
Conclusion
While preparing for a MERN Stack developer interview you have to focus on the key topics like MongoDB, Express.js, React, and Node.js which simplifies the learning & preparation.
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