Team collaboration and code review when working with Federated Modules

Federated Modules are a feature of Webpack 5 that allows you to create and consume JavaScript modules that are dynamically loaded at runtime. They enable you to share code across different applications without requiring a build step or a centralized package registry. Federated Modules allow you to create a more modular and decoupled architecture for your web applications.

However, working with Federated Modules also introduces some challenges for team collaboration and code review. How do you ensure that your code is consistent, readable, and secure across different modules and applications? How do you manage dependencies and avoid breaking changes? How do you test and debug your code in a federated environment?

In this guide, we will explore some best practices and tools for team collaboration and code review when working with Federated Modules. We will cover the following topics:

  • Code formatting and linting

  • Code documentation and comments

  • Code quality and security

  • Dependency management and versioning

  • Testing and debugging

Code formatting and linting

Code formatting and linting are essential for maintaining a consistent and readable code style across your team. They help you avoid common errors, enforce best practices, and improve the readability of your code. They also make it easier to review your code changes and spot potential issues.

There are many tools available for code formatting and linting, such as Prettier, ESLint, Stylelint, etc. You can use them to automatically format and lint your code according to a set of rules that you define or adopt from a popular style guide. You can also integrate them with your editor, IDE, or build tool to format and lint your code on save, on commit, or on build.

When working with Federated Modules, you should use the same code formatting and linting tools and rules across all your modules and applications. This will ensure that your code is consistent and compatible across different federated environments. You should also configure your tools to support the syntax and features of Federated Modules, such as dynamic imports, module federation plugins, etc.

For example, if you are using Prettier for code formatting, you can add the following options to your .prettierrc file to support dynamic imports:

{
  "parser": "babel",
  "plugins": ["@babel/plugin-syntax-dynamic-import"]
}

If you are using ESLint for code linting, you can add the following options to your .eslintrc file to support module federation plugins:

{
  "parserOptions": {
    "sourceType": "module",
    "ecmaVersion": 2020
  },
  "plugins": ["@module-federation/eslint-plugin"]
}

Code documentation and comments

Code documentation and comments are important for explaining the purpose, functionality, and usage of your code. They help you communicate your design decisions, assumptions, and limitations to other developers who work with or consume your code. They also make it easier to maintain, update, and reuse your code in the future.

There are many tools available for code documentation and comments, such as JSDoc, TypeScript Markdown, etc. You can use them to write structured and descriptive comments in your code that document the parameters, return values, types, examples, etc. of your functions, classes, variables, etc. You can also use them to generate HTML pages or PDF files that contain the documentation of your code.

When working with Federated Modules, you should use the same code documentation and comments tools and conventions across all your modules and applications. This will ensure that your code is well-documented and understandable across different federated environments. You should also document the specific aspects of Federated Modules in your code comments, such as the exposed modules, the remote modules, the shared modules, etc.

For example, if you are using JSDoc for code documentation, you can add the following tags to your comments to document the exposed modules:

/**
 * A module that exposes a greeting function.
 * @module greeting
 * @expose greeting
 */

/**
 * A function that returns a greeting message.
 * @param {string} name - The name of the person to greet.
 * @returns {string} A greeting message.
 */
export function greeting(name) {
  return `Hello ${name}!`;
}

If you are using TypeScript for code documentation, you can add the following types to your comments to document the remote modules:

/**
 * A type that represents a remote module that provides a math utility.
 * @remote math
 */
type MathModule = {
  /**
   * A function that adds two numbers
   * @param {number} x - The first number.
   * @param {number} y - The second number.
   * @returns {number} The sum of x and y.
   */
  add: (x: number, y: number) => number;
};

/**
 * A function that imports and uses a remote module.
 * @async
 * @returns {Promise<void>}
 */
async function useRemoteModule() {
  // Import the remote module using dynamic import
  const math = await import("math@http://localhost:3001/remoteEntry.js");

  // Use the remote module as a normal module
  const result = math.add(1, 2);
  console.log(result); // 3
}

Code quality and security

Code quality and security are essential for ensuring that your code is reliable, maintainable, and safe. They help you avoid bugs, errors, vulnerabilities, and performance issues that can affect the functionality and usability of your code. They also make it easier to review your code changes and ensure that they meet the quality and security standards of your team.

There are many tools available for code quality and security, such as Jest, Mocha, Chai, Sinon, Cypress, Codecov, SonarQube, Snyk, etc. You can use them to write unit tests, integration tests, end-to-end tests, code coverage reports, code analysis reports, vulnerability scans, etc. for your code. You can also integrate them with your editor, IDE, or build tool to run your tests and generate your reports on save, on commit, or on build.

When working with Federated Modules, you should use the same code quality and security tools and techniques across all your modules and applications. This will ensure that your code is tested and verified across different federated environments. You should also test and analyze the specific aspects of Federated Modules in your code, such as the dynamic loading, the module federation plugins, the shared scope, etc.

For example, if you are using Jest for unit testing, you can add the following options to your jest.config.js file to support dynamic imports:

module.exports = {
  // Use babel-jest to transform dynamic imports
  transform: {
    "^.+\\.js$": "babel-jest",
  },
  // Use @module-federation/jest-federated-module-loader to mock remote modules
  moduleNameMapper: {
    "@module-federation/jest-federated-module-loader": "@module-federation/jest-federated-module-loader",
  },
};

If you are using Codecov for code coverage reporting, you can add the following options to your .codecov.yml file to ignore the module federation plugins:

ignore:
  - "**/webpack.config.js" # Ignore webpack configuration files
  - "**/remoteEntry.js" # Ignore remote entry files generated by module federation plugins

Dependency management and versioning

Dependency management and versioning are important for managing the external modules that your code depends on. They help you specify the exact versions of the modules that your code requires, avoid conflicts and compatibility issues with other modules or applications, and update your modules when new versions are available. They also make it easier to review your code changes and ensure that they do not introduce breaking changes or regressions.

There are many tools available for dependency management and versioning, such as npm, yarn, pnpm, lerna, semver, etc. You can use them to install, update, and publish your modules to a package registry, such as npm or GitHub Packages. You can also use them to define the version ranges of your modules using semantic versioning, which indicates the level of changes in each version using major, minor, and patch numbers.

When working with Federated Modules, you should use the same dependency management and versioning tools and practices across all your modules and applications. This will ensure that your modules are installed and updated consistently and correctly across different federated environments. You should also use semantic versioning for your modules and follow the principle of backward compatibility, which means that you should not introduce breaking changes in minor or patch versions.

For example, if you are using npm for dependency management, you can add the following options to your package.json file to specify the version ranges of your dependencies using semantic versioning:

{
  "dependencies": {
    "lodash": "^4.17.21", // Accept any patch version greater than or equal to 4.17.21
    "react": "~17.0.2", // Accept any patch version greater than or equal to 17.0.2 but less than 17.1.0
    "webpack": "5.65.0" // Accept only the exact version 5.65.0
  }
}

If you are using lerna for versioning, you can add the following options to your lerna.json file to use semantic versioning for your packages:

{
  "version": "independent", // Use independent versioning for each package
  "command": {
    "version": {
      "conventionalCommits": true // Use conventional commits to determine the version bump
    }
  }
}

Testing and debugging

Testing and debugging are essential for verifying the functionality and usability of your code. They help you find and fix errors, bugs, and issues that can affect the behavior and performance of your code. They also make it easier to review your code changes and ensure that they do not introduce new errors or regressions.

There are many tools available for testing and debugging, such as Chrome DevTools, Firefox DevTools, Visual Studio Code, Webpack Dev Server, etc. You can use them to run your code in different browsers and devices, inspect and modify your code and data at runtime, set breakpoints and watch expressions, evaluate and execute your code in the console, etc. You can also integrate them with your editor, IDE, or build tool to launch and debug your code on save, on commit, or on build.

When working with Federated Modules, you should use the same testing and debugging tools and techniques across all your modules and applications. This will ensure that your code is tested and debugged across different federated environments. You should also test and debug the specific aspects of Federated Modules in your code, such as the dynamic loading, the module federation plugins, the shared scope, etc.

For example, if you are using Chrome DevTools for debugging, you can use the following steps to debug your federated modules:

  • Open the Sources panel and enable JavaScript source maps in the Settings.

  • Navigate to the webpack:// folder and find the federated modules that you want to debug.

  • Set breakpoints or log points in the federated modules as you would normally do.

  • Reload the page or trigger the dynamic import of the federated modules.

  • Observe the execution of the federated modules in the debugger.

(screenshot)

If you are using Webpack Dev Server for testing, you can use the following options to enable hot module replacement (HMR) for your federated modules:

module.exports = {
  // Enable HMR for development mode
  mode: "development",
  devServer: {
    hot: true,
  },
  plugins: [
    // Use ModuleFederationPlugin to expose or consume federated modules
    new ModuleFederationPlugin({
      // Enable HMR for federated modules
      hot: true,
      // Other options...
    }),
  ],
};