Episode 9: Using Yarn Workspace Commands to Simplify Monorepo Management

The Problem with Changing Directories

In a monorepo with multiple products and packages, you often:

1. Jump between directories to run commands for different packages.

2. Lose productivity managing these repetitive changes.

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Solution: Yarn Workspace Command

Yarn’s workspace command allows you to:

• Execute scripts or commands for a specific package from any location within the repo.

• Avoid changing directories manually.

• Manage dependencies for individual packages with ease.

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How to Use Yarn Workspace Commands

Running Scripts for a Specific Package

1. Directly from the Package Directory
   Navigate to the package directory and run the script:

    cd moduleA
    yarn build
   

2. From the Root Using yarn workspace
   Run the script from the root (or any directory) with:

    yarn workspace moduleA build
   

   • moduleA: Name of the package as defined in its package.json.

   • build: Script to execute.

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Adding Dependencies to a Specific Package

Instead of navigating to the package directory:

1. Add a dependency:

    yarn workspace moduleA add react
   

2. Check the package.json of moduleA—React is added to its dependencies.

Removing Dependencies

Use the remove command in the same way:

yarn workspace moduleA remove react

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Why This is Useful

1. Run Commands Anywhere
   Example: Run build for moduleA while inside the directory of moduleB:

    yarn workspace moduleA build
   

2. Batch Operations
   Run scripts or manage dependencies across multiple packages efficiently.

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Practical Example

Step-by-Step Use Case

1. Define Scripts in moduleA/package.json:

    {
      "scripts": {
        "build": "node index.js",
        "start": "moduleB-script"
      }
    }
   

2. Run build from Anywhere
   Navigate to the repo root or another module and execute:

    yarn workspace moduleA build
   

3. Add React to moduleA
   Without changing directories:

    yarn workspace moduleA add react
   

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Benefits of Yarn Workspace Commands

• Saves Time: Avoid unnecessary directory changes.

• Improves Workflow: Seamlessly run commands and manage dependencies.

• Monorepo-Friendly: Execute commands across packages in one place.

• Batch Operations: Combine with scripting to automate repetitive tasks across multiple packages.

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Summary

Yarn Workspace commands are a powerful feature for monorepo management. By using yarn workspace, you can:

• Run scripts for any package from any location.

• Add or remove dependencies for specific packages.

• Drastically simplify workflows in large repositories.