Top 20 Mean Stack Interview Questions

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Top 20 Mean Stack Interview Questions

With the world experiencing fast-paced digitalization, businesses are making investments in web development and programming. While full-stack, front-end, and back-end development dominate web development, new techniques and platforms are emerging for more efficient outcomes. One such platform that has gained widespread popularity in recent years is Mean stack, an open-source platform that enables programmers to employ JavaScript-based technologies and enjoy the benefits of multiple web development technologies simultaneously.

Recruiters frequently inquire about the Mean stack, the new web development platform, to select the top programmers from potential candidates. The following is a compilation of commonly asked Mean stack interview questions and their likely responses:

1. What is MongoDB used for?

It is used for storing huge volumes of data. After storing data, MongoDB further saves it in binary JSON format after completing the compilation and documentation process.

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MongoDB is a document-oriented database program that is used for storing, retrieving, and managing unstructured data. It is a NoSQL database, which means it doesn't rely on a traditional relational database structure. MongoDB is often used for its flexibility, scalability, and ease of use, making it a popular choice for web applications, mobile apps, and other projects that require handling large volumes of complex and dynamic data. Some of the typical use cases for MongoDB include content management systems, real-time analytics, and e-commerce platforms.

2. What is ExpressJS used for?

ExpressJS is a popular web framework for Node.js that is used for building web applications and APIs. It provides a robust set of features for creating web servers, handling HTTP requests and responses, routing, and middleware integration. ExpressJS is known for its simplicity, flexibility, and performance, making it a favorite among developers for building scalable and modular applications. It also has a large and active community that provides support and contributes to the development of numerous plugins and extensions.

3. What is Angular JS used for?

AngularJS is a popular front-end web framework used for building dynamic and interactive web applications. It is commonly used in the MEAN stack (MongoDB, ExpressJS, AngularJS, and Node.js) for full-stack JavaScript development. AngularJS simplifies the process of creating complex web applications by providing a set of features such as two-way data binding, dependency injection, directives, and testing support. With its powerful templating system, developers can easily create reusable components and build scalable applications. AngularJS is widely used for developing single-page applications, enterprise applications, and e-commerce platforms.

4. What is the purpose of Node.js?

Node.js is a popular JavaScript runtime built on Chrome's V8 JavaScript engine. It is commonly used in the MEAN stack (MongoDB, ExpressJS, AngularJS, and Node.js) for full-stack JavaScript development. Node.js is designed to allow developers to build scalable and high-performance applications using JavaScript on the server-side. It provides an event-driven, non-blocking I/O model that makes it efficient and suitable for building real-time applications such as chat applications, gaming platforms, and streaming platforms. Node.js also has a vast ecosystem of modules and libraries, making it easy for developers to add new functionalities to their applications.

5. What are the IDEs commonly used for the development of Node.js?

There are several popular Integrated Development Environments (IDEs) that developers commonly use for the development of Node.js applications. Some of the most widely used IDEs for Node.js development include:

  1. Visual Studio Code: a lightweight and feature-rich IDE developed by Microsoft that provides excellent support for Node.js development and debugging.
  2. WebStorm: a powerful IDE developed by JetBrains that offers advanced code editing features, debugging tools, and integration with various web technologies.
  3. Atom: a popular open-source text editor that can be customized with plugins and packages to support Node.js development.
  4. Sublime Text: a lightweight and customizable text editor that offers a range of features such as syntax highlighting, code snippets, and multiple cursors for efficient coding.
  5. Eclipse: a widely used Java-based IDE that can be extended with plugins to support Node.js development.

These IDEs provide a range of features and capabilities to support the development of Node.js applications, making it easier for developers to write, debug, and deploy their code.

6. What is REPL in Node.js?

REPL stands for Read-Eval-Print-Loop and is a built-in feature of Node.js that provides an interactive environment for developers to test and execute code snippets. It is essentially a command-line tool that allows developers to enter commands and see the results immediately, without having to write a separate program.

With the REPL, developers can quickly test small code snippets, experiment with new ideas, and debug their code. The REPL can also be used to interact with Node.js modules and APIs, making it a useful tool for learning and exploring the Node.js environment.

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To start the REPL, simply open a terminal or command prompt and type "node" followed by the Enter key. This will open the Node.js REPL, and you can start entering commands and see the results immediately.

7. What is Mongoose?

Mongoose is a popular object modelling tool used for working with MongoDB in Node.js. It provides a schema-based solution to model application data, allowing developers to define the structure of their data and the data types they want to store. Mongoose provides a simple, yet powerful API for performing CRUD (Create, Read, Update, Delete) operations on MongoDB databases, making it easier for developers to work with data in their Node.js applications.

In addition to its schema-based approach, Mongoose provides several other useful features such as data validation, middleware support, and query building capabilities. It also includes built-in support for indexing, sharding, and replication, making it easier for developers to work with large-scale MongoDB deployments.

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Overall, Mongoose is a valuable tool for Node.js developers working with MongoDB, as it simplifies the process of modeling and working with data, and provides a range of useful features for building scalable and efficient applications.

8. What is DATA modelling?

In the MEAN stack, data modelling is the process of defining the structure and relationships of data in a MongoDB database. Data modeling is a crucial step in developing a web application as it determines how data is stored, accessed, and managed by the application.

In MongoDB, data is stored in collections, which are similar to tables in traditional relational databases. However, MongoDB is a document-oriented database, which means that data is stored as documents rather than rows and columns. In data modeling, developers define the schema for each collection, specifying the fields, data types, and relationships between documents.

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Mongoose, an object modelling tool used with MongoDB in Node.js, provides a schema-based solution for data modeling. Developers can use Mongoose to define the structure of their data, validate data inputs, and perform CRUD operations on MongoDB collections.

Overall, data modelling is a critical aspect of the MEAN stack development process as it helps developers create efficient and scalable applications by organising data in a logical and structured way.

9. What does Scope in JavaScript mean?

In JavaScript, scope refers to the visibility and accessibility of variables and functions in different parts of a program.

There are two main types of scope in JavaScript: global scope and local scope. Variables declared outside of any function are considered to be in the global scope, meaning they can be accessed from anywhere in the program. On the other hand, variables declared inside a function are considered to be in the local scope and can only be accessed from within that function.

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JavaScript also has a concept of block scope, which was introduced in ES6 with the let and const keywords. Variables declared with let or const inside a block, such as a for loop or an if statement, are only accessible within that block.

When a variable is accessed in JavaScript, the runtime looks for it in the current scope, and if it is not found, it looks up the scope chain until it finds the variable. This process continues until the variable is either found or the global scope is reached.

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Understanding scope is important in JavaScript programming, as it helps developers write code that is efficient, maintainable, and bug-free. By properly managing scope and avoiding global variables when possible, developers can avoid conflicts and unintended consequences in their code.

10. What is the difference between binary and linear research?

The two types of search algorithms are binary search and linear search.

Binary search is an efficient algorithm used to search for a specific value in a sorted array or list. The algorithm works by repeatedly dividing the search interval in half until the value is found or determined to not be present in the array. Since binary search only considers half of the remaining array in each iteration, it has a time complexity of O(log n), making it more efficient than linear search for large arrays.

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On the other hand, linear search is a simple algorithm used to search for a specific value in an unsorted array or list. The algorithm works by sequentially checking each element of the array until the value is found or the end of the array is reached. Since linear search checks each element of the array, it has a time complexity of O(n), making it less efficient than binary search for large arrays.

In summary, binary search is more efficient for searching sorted arrays or lists, with a time complexity of O(log n), while linear search is useful for searching unsorted arrays or lists, with a time complexity of O(n).

11. State the difference between AJAX, jQuery, and Node.js?

AJAX, jQuery, and Node.js are all JavaScript-based technologies used for developing web applications, but they have different purposes and use cases.

AJAX stands for Asynchronous JavaScript and XML. It is a web development technique that allows web pages to update content dynamically without having to reload the entire page. AJAX uses a combination of JavaScript and XML (or JSON) to make asynchronous requests to the server and retrieve data without disrupting the user's experience on the web page.

jQuery is a popular JavaScript library that simplifies HTML document traversal, event handling, and animation for rapid web development. jQuery provides a set of methods and functions that allow developers to write less code and achieve more functionality in their web applications. jQuery also has AJAX support built-in, making it easier to perform AJAX requests and handle responses.

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Node.js, on the other hand, is a server-side JavaScript runtime environment. It allows developers to use JavaScript for back-end development, providing a platform for building fast, scalable, and high-performance web applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, ideal for building real-time web applications.

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In summary, AJAX is a web development technique for dynamic content updates, jQuery is a JavaScript library that simplifies web development, and Node.js is a server-side JavaScript runtime environment for building fast and scalable web applications. While they all have different purposes and use cases, they can be used together to create robust and efficient web applications.

12. Highlight functions of Dependency Injection

Dependency Injection is a design pattern used in software engineering that aims to increase the flexibility, modularity, and maintainability of software by decoupling its components and reducing the dependencies between them. Here are some of the key functions of Dependency Injection:

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  1. Decoupling of components: Dependency Injection helps to decouple components by removing direct dependencies between them. Instead of components relying on each other directly, they are loosely coupled through interfaces or abstract classes, making it easier to replace, modify or extend individual components without affecting the others.
  2. Flexibility and modularity: With Dependency Injection, components can be developed independently of each other, allowing for greater flexibility and modularity. This means that individual components can be swapped in and out of the system without affecting the rest of the application, making it easier to add new features or improve existing ones.
  3. Testability: Dependency Injection makes it easier to test software components in isolation. By decoupling the components, it is possible to test each component individually, using mock or fake objects to simulate dependencies. This improves the reliability and accuracy of testing, making it easier to identify and fix bugs.
  4. Centralised configuration: Dependency Injection allows for centralized configuration of components, making it easier to manage and maintain large software systems. By configuring components in one place, changes can be made quickly and easily, without having to modify multiple files or components.
  5. Reusability: With Dependency Injection, components can be reused across different applications, making it easier to develop new software systems. This helps to reduce development time and costs, and ensures that the software is consistent and reliable across different applications.

In summary, Dependency Injection is a design pattern that improves the flexibility, modularity, and maintainability of software by decoupling components, making them easier to test, configure, and reuse.

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13. What does Containerisation mean?

In the context of MEAN stack development, containerisation refers to the process of encapsulating the application and its dependencies into containers using containerisation tools such as Docker.

MEAN stack development involves the use of several technologies such as MongoDB, Express.js, Angular, and Node.js. These technologies have their own dependencies and configurations that need to be set up to run the application. Containerisation makes it possible to package all of these components and dependencies into a single container, making it easier to deploy, manage, and scale the application.

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By containerising the MEAN stack application, developers can create a portable and self-contained environment that can run consistently across different computing environments, including development, testing, and production. This helps to reduce the complexities of deploying and managing MEAN stack applications, making it easier to develop and maintain complex applications.

14. State most significant features of Test Pyramid

The Test Pyramid is a framework for designing software testing strategies that emphasizes the importance of different types of tests at different levels of the testing process. Its key features include a broad base of unit tests, fewer but more comprehensive integration tests, and a small number of end-to-end tests at the top. This approach helps to improve the reliability, efficiency, and effectiveness of software testing while reducing the overall cost and effort required.

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15. What is the purpose of Indexes in MongoDB?

Indexes in MongoDB are used to improve the performance of database queries by allowing faster access to data. They help to reduce the number of documents that need to be scanned to find the desired data, thereby improving query response times. Indexes can be created on one or more fields of a collection and can be customised to suit specific query patterns.

16. In TypeScript, what features differentiate Classes from Interfaces?

Classes in TypeScript are a blueprint for creating objects with specific properties and methods, while interfaces are a way to define the shape of an object. Classes provide implementation details and can be used to create instances, while interfaces only define the structure of an object and cannot be instantiated. Classes also support inheritance and encapsulation, while interfaces do not.

17. State the function of Decorators in TypeScript

Decorators in TypeScript are a feature that allows developers to add metadata and functionality to classes, methods, properties, and parameters. They can be used for a variety of purposes, including logging, validation, and performance optimisation. Decorators provide a way to modify the behaviour of existing code without changing its implementation, making it easier to maintain and extend.

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18. Define what Callback means in Node.js

In Node.js, a callback is a function that is passed as an argument to another function and is executed when that function has completed its task. Callbacks are used to handle asynchronous operations, such as file I/O or network requests, and are an essential part of Node.js programming. They allow the program to continue executing while waiting for a response, making Node.js applications fast and scalable.

19. What is Cross-site Scripting (XSS)?

Cross-site scripting (XSS) is a type of security vulnerability in which attackers inject malicious scripts into web pages viewed by other users. These scripts can be used to steal sensitive information or hijack user sessions. XSS attacks can be prevented by validating user input and encoding output to prevent script injection.

20. What is the function of the grid system in CSS?

The grid system in CSS is a layout tool that enables developers to create responsive designs for web pages. It consists of a set of classes that define the size and position of elements on a web page based on a grid of columns and rows. The grid system makes it easier to design and maintain consistent layouts across different devices and screen sizes. It allows developers to create complex layouts with ease, without having to use complex CSS positioning and float properties.

Although the questions mentioned are not all that can be asked in an interview, they cover the basics of Mean Stack in detail.

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TWT Staff

TWT Staff

Writes about Programming, tech news, discuss programming topics for web developers (and Web designers), and talks about SEO tools and techniques