MEAN vs NestJS: What are the differences?

Introduction

This Markdown code provides a comparison between MEAN (MongoDB, Express.js, Angular, Node.js) and NestJS, highlighting their key differences.

1. Coding Language: MEAN stack predominantly uses JavaScript for coding, whereas NestJS utilizes TypeScript, a statically typed superset of JavaScript, for coding. TypeScript offers features like strict typing, interfaces, and decorators, enabling better IDE support, improved code maintainability, and enhanced scalability.

2. Modularity and Scalability: While both MEAN and NestJS provide modularity, NestJS leverages an opinionated modular architecture pattern called "Modules" to create self-contained and reusable modules effortlessly. This design pattern promotes code reusability, maintainability, and scalability, making it easier to manage larger projects with ease.

3. Middleware and Exception Handling: MEAN stack relies on Express.js middleware for handling HTTP requests and errors. In contrast, NestJS provides an advanced middleware system, including built-in pipes, guards, and interceptors, ensuring better control and validation of incoming requests. NestJS also adopts an Exception Filter concept to handle exceptions globally and return appropriate error responses.

4. ORM and Database Integration: MEAN stack typically uses MongoDB as the NoSQL database, and developers typically interact with it using the native MongoDB driver or Mongoose. On the other hand, NestJS incorporates TypeORM and Sequelize as popular Object-Relational Mapping (ORM) libraries, offering support for various databases like MySQL, PostgreSQL, and SQLite. These ORM libraries provide easy database integration, query builders, and additional features like migrations and relationships.

5. Architecture and Dependency Injection: MEAN stack is more loosely structured, allowing developers to choose their preferred frameworks and patterns. In contrast, NestJS follows a structured and opinionated architecture based on Angular's concepts, including modules, controllers, services, and providers. This architectural approach promotes code organization, separation of concerns, and dependency injection, enhancing testability and maintainability.

6. Community Support and Ecosystem: MEAN stack has a well-established and mature community, with a vast number of resources, tutorials, and libraries available to facilitate development. However, NestJS, being relatively new, has a rapidly growing community that actively contributes to its ecosystem. NestJS provides its own CLI tool, NestJS CLI, for creating and managing projects, which simplifies the development process.

In summary, MEAN stack primarily uses JavaScript, while NestJS leverages TypeScript, and NestJS offers a more opinionated modular architecture, advanced middleware system, ORM libraries for database integration, structured architecture with dependency injection, and an actively growing community, making it a robust and scalable framework for modern web development.