The Treasure Trove of Backstage Monorepo: Perfect Utilization of “common-library”

Hello everyone! Today, we’re going to take an in-depth look at the “common-library” role, which plays a very important part in Backstage’s package management system. 🚀

As a Backstage project grows, utility functions and UI components that are commonly used across multiple plugins naturally emerge. The “common-library” is used to prevent code duplication and manage these efficiently. 💡

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🏗️ Understanding Backstage’s Package Role System

Backstage assigns a ‘role’ to each package to efficiently build and manage numerous packages within a monorepo. This is specified in the backstage.role field of the package.json file, and the way build tools and the system process the package changes according to this role.

Among these, “common-library” is, as its name suggests, like a ‘common treasure trove’.

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🌟 Core Purpose of the “common-library” Package

The primary purpose of this role is to share components or utilities that can be reused across various other packages.

It’s not just for use within a specific plugin; it’s about gathering universally used code throughout the entire project.

✅ Detailed Explanation of Key Roles

• Share Reusable Components: Defines common button styles, layout components, etc., used across multiple frontend plugins, helping maintain a consistent UI.
• Provide Utility Functions: Offers frequently used business logic or helper functions, such as date format conversion and API response handling logic.
• Eliminate Code Duplication Between Plugins: Maximizes maintenance efficiency by allowing plugins to reference the library instead of copying and pasting identical code into each one.

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🛠️ Practical Application: package.json Configuration Example

If you want to create a common utility package in your project, configure it as follows:

JSON

{
  "name": "@internal/common-utils",
  "version": "1.0.0",
  "backstage": {
    "role": "common-library"  // 👈 Define the role here.
  },
  "dependencies": {
    "lodash": "^4.17.21"
  }
}

Through this configuration, the Backstage CLI recognizes, “Ah, this package is a library to be used elsewhere!” and applies the appropriate build process.

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🏁 Conclusion: An Essential Choice for a Clean Monorepo

The “common-library” is a strong supporter that protects the code quality and consistency of your Backstage project. By properly separating and managing commonly used functionalities with this role, you won’t fear maintenance, no matter how large your project grows! 🚀

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