Node.js vs NestJS – Understanding their Technical Difference
Tags: node, nestjs, javascript, jscript
Published: 2023-12-11 13:23:15

Node.js and NestJS are both popular JavaScript platforms for building efficient, scalable server-side applications. Node.js is a runtime that allows developers to use JavaScript on the server, while NestJS is a framework that builds on top of Node.js, providing more structure and scalability out-of-the-box.

Both have their pros and cons and are better suited for certain types of applications. At a high level, Node.js offers more flexibility and works well for simple APIs and microservices, while NestJS shines when building complex, enterprise-grade applications thanks to its robust feature set.

This article will provide an overview of both platforms, compare their architectures and performance, discuss factors to consider when choosing one or the other, and make some recommendations on when NestJS is the better option over plain Node.js or vice versa.

## Node.js Overview
Node.js exploded in popularity upon its release in 2009, thanks to its ability to execute JavaScript code outside of the browser, its efficient use of asynchronous/non-blocking I/O, and its support for real-time applications.

Instead of waiting for requests and responses to complete before moving to another task, Node.js uses an event loop that allows it to handle high volumes of concurrent requests without incurring the overhead of managing threads. This makes Node.js well-suited for data-intensive real-time applications like chat rooms and streaming platforms.

### Benefits of Node.js

- Large ecosystem of open-source libraries and tools
- Great for prototyping and iterating quickly
- Lean and fast compared to other server-side frameworks
- JavaScript skills transfer nicely from front-end

### Downsides of Node.js

- Limited structure and architecture can be chaotic
- Heavy use of callbacks can lead to callback hell
- Not great for complex or enterprise-grade applications
- Must assemble most features yourself

Hence, Node.js is a great choice for lightweight web applications, simple APIs and microservices, anything requiring real-time data, and MVPs or prototypes where flexibility and speed of iteration is key.

## NestJS Overview
Released in 2016, NestJS provides an out-of-the-box application architecture for building scalable Node.js servers using JavaScript/TypeScript. It officially bills itself as "a progressive Node.js framework for building enterprise-grade efficient, reliable, and scalable server-side applications."

### Capabilities of NestJS

- Built-in support for a modular organization using controllers, providers, modules, and more
- Sophisticated dependency injection system
- A CLI tool for the generation of boilerplate code
- Easy to implement middleware and guards thanks to built-in decorators
- Exception filters for centralized error handling
- Framework for unit and e2e testing

By providing structure, NestJS makes larger applications much easier to maintain and expand. The learning curve is a bit steeper than Node, but they’ve done a great job making documentation and training resources readily available.

Downsides compared to Node.js are mainly increased complexity and tighter coupling to the NestJS platform. The framework handles so much automatically that migrating away later requires significant refactoring.

### Use cases where NestJS shines over bare Node.js

- Highly scalable applications needing easy maintenance
- Anything with intricate business logic or complex flows
- Teams with less experienced Node developers
- When unit testing and sound architecture are key
- Processing lots of data across distributed systems
- CRUD APIs requiring validation, authorization, logging automatically

Hence, while Node.js gives you a canvas and brush to create your own masterpiece, NestJS provides a rich set of paint-by-numbers features so engineering teams can build robust applications faster.

## Differences between NodeJS and NestJS

### Comparing Architectures
There are quite a few differences between Node.js and NestJS under the hood, but we’ll focus on some key ones around file structure and request handling flow.

### File Structure
A typical Node.js application might just throw all server logic into a single index.js file, or separate concerns across a simple controllers/, services/, models/ type folder structure. NestJS enforces further modularization using:

- Controllers: Handle incoming requests and return responses
- Providers: Services that contain core business logic, interacting with databases, making API calls, etc.
- Modules: Self-contained units of business capabilities that group related controllers/providers
- Middleware: Functions executed during the request handling pipeline
- Guards: Functions that control access to specific endpoints

### Request Handling Flow
When a request comes into a Node.js app, you manually take that request and route it across any number of modules, controllers, and services you’ve wired up. Any middleware needs to be explicitly inserted as well.

NestJS sets things up differently using dependency injection and a built-in IoC container. A request first hits any global middleware then flows through a pipeline roughly like:

```
Request -> Guard -> Interceptor -> 
    -> Controller -> Service -> Repository

```
It provides standardization and consistency across implementations.

### Performance
As far as runtime performance and benchmarks, NestJS introduces minimal overhead over Node, usually less than 1%. For example, a common benchmark serving JSON shows Node.js at ~31k requests/second and NestJS at ~30k.

So, in terms of pure speed, the two are very comparable. Where Nest really accelerates development velocity is through its robust feature set and architectural conventions.

Considerations in Deciding Which one to choose. NodeJS or NestJS
When embarking on a new project, how do you decide whether to use NestJS versus plain Node.js? Here are some factors to weigh.

### Team & Project

- Team experience level with Node/Nest and typescript
- App complexity and size
- Desired development velocity
- Availability of quality Node.js dev resources

### Business Factors

- Target users and expected traffic
- Pace of enhancement/feature requests
- Application availability/stability needs
- Compliance requirements

### Technical Factors

- Integration needs with external services/databases
- Real-time requirements like chat or streaming
- Need for scalability/maintainability
- Testing needs and CI/CD processes

If your team is familiar with Node and TypeScript, starting with NestJS as the baseline for almost any material project is likely to pay off exponentially in long-term velocity and stability.

## Summary and Recommendations
To summarize the key differences:

- Node.js offers ultimate flexibility while NestJS provides structure and conventions
- Node good for simple real-time services and micro front-ends.
- Nest enables robust complex applications, with integrated best practices
- Nest has steeper initial learning curve
Here are some quick rules of thumb on when to default to each:

### Node.js

- Simple CRUD APIs and microservices
- Prototyping ideas where speed matters most
- Front-end Node microservices
- Public-facing real-time features
NestJS

- Nearly everything else!
- Internal enterprise applications
- Heavy business logic
- Cross functional/database integrations
- Legacy codebases benefitting modernization
- Prioritizing maintainability

The overhead NestJS introduces gets paid back over the long haul via accelerated development velocity, clean architecture, and easy maintainability. Unless building a public API to support millions of users per day, teams are usually better served starting with NestJS from the get-go.