Introduction to Nx Plugins and Nx Devkit
Tags: nx, plugins, typescript, devrel
Published: 2023-05-09 20:42:41

Welcome to the first blog post in our series on creating custom Nx plugins! This post targets developers who are familiar with the basics of the Nx ecosystem but have never built a plugin for Nx before. In this article, we'll explore the importance of Nx plugins, introduce the Nx Devkit, and discuss the core concepts and basic structure of an Nx plugin. Let's dive in!

## Table of Contents:

1. Why Nx Plugins Matter
2. The Nx Devkit
3. Core Concepts of Nx Devkit
4. The Basic Structure of an Nx Plugin
5. Summary

## Why Nx Plugins Matter
Nx plugins play a crucial role in the Nx ecosystem, as they extend the functionality of an Nx workspace. By creating custom Nx plugins, developers can tailor the Nx experience to their specific project requirements, streamline workflows, and enhance productivity. Moreover, Nx plugins can be shared as npm packages or directly referenced within a single repo, allowing developers to leverage the power of the Nx community and build on the work of others.

## The Nx Devkit

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/n0tu0pfaamafr8fr6kk1.png)
The Nx Devkit is the foundation for creating Nx plugins. It provides a simple and powerful API for creating generators and executors, which are the primary building blocks of Nx plugins. By using the Nx Devkit, developers can write custom code that seamlessly integrates with the underlying Nx core and benefits from its powerful features, such as computation caching and code generation.

## Core Concepts of Nx Devkit

The Nx Devkit is based on a few core concepts:

1. **Executors**: Executors are responsible for running tasks within an Nx workspace. They define how a specific task should be executed, such as building, testing, or deploying an application.
2. **Generators**: Generators are responsible for generating code or modifying the workspace structure based on predefined templates and user input. They simplify repetitive tasks and enforce best practices.
3. **Language Primitives and Immutable Objects**: The Nx Devkit relies on language primitives and immutable objects, with the tree being the only exception. This simplicity makes the Devkit easy to understand and work with.


The Nx Devkit offers a set of core APIs and utilities to help developers get started with their plugin:
1. `Tree`: An in-memory file system representation that allows for manipulating files and directories in the workspace. It is used by generators to make changes to the workspace.
2. `ProjectConfiguration`: A utility for managing project configuration in an Nx workspace.
3. `runExecutor`: A function for running executors programmatically, useful for testing.
4. `readJson`: A utility for reading JSON files in the workspace.
5. `writeJson`: A utility for writing JSON files in the workspace.
6. `generateFiles`: A utility for generating files from templates.

These tools make it easier for developers to create and test Nx plugins while ensuring compatibility with the Nx ecosystem.

## The Basic Structure of an Nx Plugin
An Nx plugin consists of the following main components:

1. `executors.json`: This file registers executors in the plugin.
2. `generators.json`: This file registers generators in the plugin.
3. `src/`: This directory contains the source code for the plugin's executors and generators.
4. `package.json`: Contains references to the generators and executors schematics.

Example of a simple package.json:

```json
{
  "name": "@org/my-custom-plugin",
  "version": "1.0.0",
  "main": "src/index.js",
  "generators": "./generators.json",
  "executors": "./executors.json",
  "devDependencies": {
    ...
  },
  "peerDependencies": {
    ...
  }
}
```

## Summary
In this introductory blog post, we've covered the importance of Nx plugins, introduced the Nx Devkit, and discussed the core concepts of the Nx Devkit. We also looked at the basic structure of an Nx plugin. In the next blog post, we'll dive deeper into generators and guide you through creating a simple generator step by step. Stay tuned!