Adding Nx to your Existing Project

Nx can be added to any type of project, not just monorepos. The main benefit is to get caching abilities for the package scripts. Each project usually has a set of scripts in the package.json:

package.json
{
  ...
  "scripts": {
    "build": "next build",
    "lint": "eslint ./src",
    "test": "node ./run-tests.js"
  }
}

You can make these scripts faster by leveraging Nx's caching capabilities. For example:

You change some spec files: in that case the build task can be cached and doesn't have to re-run.
You update your docs, changing a couple of markdown files: then there's no need to re-run builds, tests, linting on your CI. All you might want to do is trigger the Docusaurus build.

Install Nx on a Non-Monorepo Project

Run the following command:

❯

npx nx@latest init

Running this command will ask you a few questions about your workspace and then set up Nx for you accordingly. The setup process detects tools which are used in your workspace and suggests installing Nx plugins to integrate the tools you use with Nx. Running those tools through Nx will have caching enabled when possible, providing you with a faster alternative for running those tools. You can start with a few to see how it works and then add more with the nx add command later. You can also decide to add them all and get the full experience right away because adding plugins will not break your existing workflow.

The first thing you may notice is that Nx updates your package.json scripts during the setup process. Nx Plugins setup Nx commands which run the underlying tool with caching enabled. When a package.json script runs a command which can be run through Nx, Nx will replace that script in the package.json scripts with an Nx command that has caching automatically enabled. Anywhere those package.json scripts are used, including your CI, will become faster when possible. Let's go through an example where the @nx/next/plugin and @nx/eslint/plugin plugins are added to a workspace with the following package.json.

package.json
{
  "name": "my-workspace",
  ...
  "scripts": {
-     "build": "next build && echo 'Build complete'",
+     "build": "nx next:build && echo 'Build complete'",
-     "lint": "eslint ./src",
+     "lint": "nx eslint:lint",
    "test": "node ./run-tests.js"
  },
+   "nx": {}
}

The @nx/next/plugin plugin adds a next:build target which runs next build and sets up caching correctly. In other words, running nx next:build is the same as running next build with the added benefit of it being cacheable. Hence, Nx replaces next build in the package.json build script to add caching to anywhere running npm run build. Similarly, @nx/eslint/plugin sets up the nx eslint:lint command to run eslint ./src with caching enabled. The test script was not recognized by any Nx plugin, so it was left as is. After Nx has been setup, running npm run build or npm run lint multiple times, will be instant when possible.

You can also run any npm scripts directly through Nx with nx build or nx lint which will run the npm run build and npm run lint scripts respectively. In the later portion of the setup flow, Nx will ask if you would like some of those npm scripts to be cacheable. By making those cacheable, running nx build rather than npm run build will add another layer of cacheability. However, nx build must be run instead of npm run build to take advantage of the cache.

Inferred Tasks

You may have noticed that @nx/next provides dev and start tasks in addition to the next:build task. Those tasks were created by the @nx/next/plugin plugin from your existing Next.js configuration. You can see the configuration for the Nx Plugins in nx.json:

nx.json
{
  "plugins": [
    {
      "plugin": "@nx/eslint/plugin",
      "options": {
        "targetName": "eslint:lint"
      }
    },
    {
      "plugin": "@nx/next/plugin",
      "options": {
        "buildTargetName": "next:build",
        "devTargetName": "dev",
        "startTargetName": "start"
      }
    }
  ]
}

Each plugin can accept options to customize the projects which they create. You can see more information about configuring the plugins on the @nx/next/plugin and @nx/eslint/plugin plugin pages.

To view all available tasks, open the Project Details view with Nx Console or use the terminal to launch the project details in a browser window.

❯

nx show project my-workspace --web

Project Details View

my-workspace

Root: .

Type:library

Targets

dev
next dev
eslint:lint
eslint ./src
Cacheable
next:build
next build
Cacheable
start
next start

The project detail view lists all available tasks, the configuration values for those tasks and where those configuration values are being set.

Configure an Existing Script to Run with Nx

If you want to run one of your existing scripts with Nx, you need to tell Nx about it.

Preface the script with nx exec -- to have npm run test invoke the command with Nx.
Define caching settings.

The nx exec command allows you to keep using npm test or npm run test (or other package manager's alternatives) as you're accustomed to. But still get the benefits of making those operations cacheable. Configuring the test script from the example above to run with Nx would look something like this:

package.json
{
  "name": "my-workspace",
  ...
  "scripts": {
    "build": "nx next:build",
    "lint": "nx eslint:lint",
    "test": "nx exec -- node ./run-tests.js"
  },
  ...
  "nx": {
    "targets": {
      "test": {
        "cache": "true",
        "inputs": [
          "default",
          "^default"
        ],
        "outputs": []
      }
    }
  }
}

Now if you run npm run test or nx test twice, the results will be retrieved from the cache. The inputs used in this example are as cautious as possible, so you can significantly improve the value of the cache by customizing Nx Inputs for each task.

Set Up CI for Your Workspace

This tutorial walked you through how Nx can improve the local development experience, but the biggest difference Nx makes is in CI. As repositories get bigger, making sure that the CI is fast, reliable and maintainable can get very challenging. Nx provides a solution.

Nx reduces wasted time in CI with the affected command.
Nx Replay's remote caching will reuse task artifacts from different CI executions making sure you will never run the same computation twice.
Nx Agents efficiently distribute tasks across machines ensuring constant CI time regardless of the repository size. The right number of machines is allocated for each PR to ensure good performance without wasting compute.
Nx Atomizer automatically splits large e2e tests to distribute them across machines. Nx can also automatically identify and rerun flaky e2e tests.

Generate a CI Workflow

If you are starting a new project, you can use the following command to generate a CI workflow file.

❯

npx nx generate ci-workflow --ci=github

Choose your CI provider

You can choose github, circleci, azure, bitbucket-pipelines, or gitlab for the ci flag.

This generator creates a .github/workflows/ci.yml file that contains a CI pipeline that will run the lint, test, build and e2e tasks for projects that are affected by any given PR.

The key line in the CI pipeline is:

- run: npx nx affected -t lint test build e2e-ci

Connect to Nx Cloud

Nx Cloud is a companion app for your CI system that provides remote caching, task distribution, e2e tests deflaking, better DX and more.

To connect to Nx Cloud:

Commit and push your changes
Go to https://cloud.nx.app, create an account, and connect your repository

Connect to Nx Cloud Manually

If you are not able to connect via the automated process at https://cloud.nx.app, you can connect your workspace manually by running:

❯

npx nx connect

You will then need to merge your changes and connect to your workspace on https://cloud.nx.app.

Enable a Distributed CI Pipeline

The current CI pipeline runs on a single machine and can only handle small workspaces. To transform your CI into a CI that runs on multiple machines and can handle workspaces of any size, uncomment the npx nx-cloud start-ci-run line in the .github/workflows/ci.yml file.

- run: npx nx-cloud start-ci-run --distribute-on="5 linux-medium-js" --stop-agents-after="e2e-ci"

For more information about how Nx can improve your CI pipeline, check out one of these detailed tutorials:

Migration