Introduction
Nest (NestJS) is a framework for building efficient, scalable Node.js server-side applications. It uses progressive JavaScript, is built with and fully supports TypeScript (while still letting you write plain JavaScript), and combines elements of OOP (object-oriented programming), FP (functional programming), and FRP (functional reactive programming).
Under the hood, Nest uses robust HTTP server frameworks such as Express (the default), and can optionally be configured to use Fastify instead.
Nest provides a level of abstraction above these common Node.js frameworks (Express and Fastify), but also exposes their APIs directly to the developer. This gives you the freedom to use the myriad third-party modules available for the underlying platform.
Philosophy#
In recent years, thanks to Node.js, JavaScript has become the "lingua franca" of the web for both frontend and backend applications. This has given rise to projects like Angular, React, and Vue, which improve developer productivity and enable the creation of fast, testable, and extensible frontend applications. However, while plenty of excellent libraries, helpers, and tools exist for Node.js (and server-side JavaScript), none of them effectively solves the main problem of architecture.
Nest provides an out-of-the-box application architecture that lets developers and teams create highly testable, scalable, loosely coupled, and maintainable applications. The architecture is heavily inspired by Angular.
Installation#
To get started, you can either scaffold the project with the Nest CLI or clone a starter project. Both produce the same outcome.
To scaffold the project with the Nest CLI, run the following commands. They create a new project directory and populate it with the initial core Nest files and supporting modules, giving your project a conventional base structure. We recommend the Nest CLI for first-time users, and the First steps chapter continues with this approach.
$ npm i -g @nestjs/cli
$ nest new project-name
Alternatives#
Alternatively, you can install the TypeScript starter project with Git:
$ git clone https://github.com/nestjs/typescript-starter.git project
$ cd project
$ npm install
$ npm run start
Hint To clone the repository without its Git history, use degit.
Open your browser and navigate to http://localhost:3000/.
To install the JavaScript flavor of the starter project, use javascript-starter.git in the command sequence above.
You can also start a new project from scratch by installing the core and supporting packages yourself. In that case, you need to set up the project boilerplate files on your own. At a minimum, you need these dependencies: @nestjs/core, @nestjs/common, rxjs, and reflect-metadata. For a walkthrough of creating a complete project this way, see 5 steps to create a bare minimum NestJS app from scratch.
