Adding Nx to Lerna/Yarn/PNPM/NPM Workspace

Interested in migrating from Lerna in particular? In case you missed it, Nrwl, the company behind Nx, took over stewardship of Lerna. This allows for a much better integration between the two. Read more in our dedicated guide.

Short story: you can use Nx easily together with your current Lerna/Yarn/PNPM/NPM monorepo setup. Why? To speed up your tasks by leveraging Nx's powerful scheduling and caching capabilities.

Adding Nx is a low impact operation that does not require any particular change to your repository like how your packages and scripts are organized. Whatever setup you have still works the same way but faster and with better dev ergonomics. You could manually configure Nx, but it is way easier by running the following command:

npx add-nx-to-monorepo

Watch this 3-min video to see how the command works and what next steps are:

npx add-nx-to-monorepo does the following:

  1. Add Nx to your package.json.
  2. Create nx.json, containing all the necessary configuration for Nx.
  3. Set up Nx Cloud (if you chose "yes").

If you are familiar with Turborepo, check out this guide. At this point, Nx can do anything Turbo can, and much more.

What You Get Right Away

This sets up Nx core in your existing monorepo which comes with a series of interesting features that help intelligenty schedule tasks and make sure operations are quick:

  • Run any npm script - with Nx installed, you can use it's powerful task scheduler which automatically picks up your npm scripts from your package's script section. For instance if package myproj has a build script, you can just run it using nx build myproj. Similarly for running tests use nx test myproj and so on.
  • Parallelization and task dependencies - Nx automatically knows how your projects relate to each other. As a result, if project-a depends on project-b and you run nx build project-a, Nx first runs the builds for all of project-a's dependencies, in this specific example it builds project-b before project-a.
  • Only run what changed - Using Nx affected commands you only really execute tasks on the projects that changed, compared to a given baseline (usually the main branch).
  • Caching - You get Nx's computaton caching for free. All operations, including artifacts and terminal output are restored from the cache (if present) in a completely transparent way without disrupting your DX. No configuration needed. Obviously this results in an incredible speed improvement.
  • Distributed Task Execution - This is unique to Nx. In combination with Nx Cloud your tasks are automatically distributed across CI agents, taking into account build order, maximizing parallelization and thus agent utilization. It even learns from previous runs to better distribute tasks! Learn more
  • Interactive workspace visualization - Nx comes with a project graph visualization built-in which you can use to interactively explore your workspace, understand dependencies and find paths between nodes and why they exist.
  • Dedicated VSCode extension - You can install Nx Console which is a dedicated VSCode extension to provide a visual interface for navigating your monorepo workspace in terms of launching commands as well as for generating code.
  • GitHub integration - Install the Nx Cloud Github App to get inline reporting on your CI jobs.

Looking for integrating Lerna and Nx?

Check out our dedicated guide: Lerna and Nx

Further customizations

Here are some further customizations we found to be useful when adding Nx to existing monorepos.

Excluding Sources

The add-nx-to-monorepo command does its best to figure out what projects you have in the repo. Similar to other tools, it looks at the workspaces property in the root package.json and tries to find all package.json files matching the globs. You can change those globs to exclude some projects. You can also exclude files by creating an .nxignore file, like this:

third_party # nx will ignore everything in the third-party dir

Enabling JS Analysis

The add-nx-to-monorepo command adds the following to the generated nx.json. This disables JS analysis, such that Nx only analyzes package.json files like Lerna or Turborepo.

2  "pluginsConfig": {
3    "@nrwl/js": {
4      "analyzeSourceFiles": false
5    }
6  }

We do this because most existing Lerna monorepos have implicit dependencies between projects Lerna knows nothing about. By adding "analyzeSourceFiles": false we are trying to make sure that Nx sees the same project graph Lerna does, even though the graph is often incorrect.

You can remove the section in the config, which will enable the JS/TS analysis. In this case Nx will consider all import and require statements in your JS/TS files when creating its project graph. If you do that, you can also add the paths property to the root tsconfig.base.json (if you don't have this file, create it), which will tell Nx how to resolve imports.

2  "compilerOptions": {
3    "paths": {
4      "one": ["packages/one/index"],
5      "one/*": ["packages/one/*"],
6      "two": ["packages/two/index"],
7      "two/*": ["packages/two/*"]
8    }
9  }

Next Steps

Nx is like a VS Code of build tools. It has a very powerful core, but it's really the plugins and extra capabilities that really transform how you develop.

Nx has first class support for React, Next.js, React Native, Angular, Node, NestJS, Jest, Cypress, Storybook and many more. All the plugins are designed to work together and create a cohesive and pleasant to use dev environment.

In addition, Nx makes a lot of things much easier, like building large apps incrementally, distributing CI (no point in doing caching unless you can do that), enforcing best practices, building design systems.

Real world examples of using add-nx-to-monorepo

Speeding Up Facebook React Monorepo with Nx

Speeding Up Remotion Monorepo with Nx

Speeding Up Storybook Monorepo with Nx