Initializing Yarn Workspaces for Monorepos with Multiple Lock Files

When working with monorepos that contain multiple workspaces, one common issue is the lack of yarn.lock files specific to each workspace. This becomes particularly problematic when trying to package a single workspace into a docker image or other environment outside of the monorepo. In this article, we'll explore how to initialize yarn workspaces for monorepos with multiple lock files.

The Problem with Single Yarn Lock Files

By default, yarn workspaces create a single yarn.lock file at the root of the project. While this can be convenient for managing dependencies across multiple workspaces, it has one significant drawback: when you want to package a single workspace into a separate environment, you'll lose the benefits of a lock file that knows exactly which dependencies are being used.

For example, let's say we have a monorepo with two workspaces: `workspace-a` and `workspace-b`. `workspace-a` uses some exported modules from `workspace-b`, but when we try to package `workspace-a` into a docker image, we'll be missing the yarn.lock file that would ensure consistent dependency versions.

The Solution: Initializing Yarn Workspaces with Multiple Lock Files

To overcome this limitation, we need a way to generate yarn.lock files for individual workspaces within our monorepo. While there doesn't seem to be an existing issue or feature request for this functionality, it's certainly possible using some creative configuration and scripting.

Configuring Vercel Projects for Ignored Build Steps

To illustrate the potential solution, let's consider a scenario where we have two Vercel projects connected to the same repository: `apps/frontend` (Create React App) and `apps/nextapp` (Next.js). By configuring the Ignored Build Step option inside the Git section of our Project Settings on Vercel, we can trigger deployments only when changes occur in specific directories.

For example, we could set up the Ignored Build Step for each project as follows:

* For the Create React App project: `git diff HEAD^ HEAD -quiet` with a root directory of `apps/frontend`

* For the Next.js project: `git diff HEAD^ HEAD -quiet` with a root directory of `apps/nextapp`

This would allow us to trigger deployments for each project independently, without affecting the other.

In conclusion, initializing yarn workspaces for monorepos with multiple lock files requires some creative configuration and scripting. By leveraging Vercel's Ignored Build Step option and configuring our projects accordingly, we can achieve greater flexibility and control over our build processes. Whether you're working on a complex monorepo or simply want to package individual workspaces into separate environments, this approach offers a promising solution for managing dependencies and ensuring consistent builds across your project ecosystem.

yarn workspaces init: A command that would generate yarn.lock files specific to each workspace within our monorepo. This feature request would greatly simplify the process of packaging individual workspaces into separate environments, making it an essential addition to the yarn workspaces functionality.

Yarn workspaces init