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Angular

Display App Version in Angular: A Simple Guide

By Filip on 10/05/2024

Learn different techniques and best practices for displaying your Angular application's version number within the user interface.

Display App Version in Angular: A Simple Guide

Table of Contents

Introduction

This article explains how to display your Angular application's version effectively. It covers accessing the version from package.json using environment files, implementing build-time replacement for dynamic updates, and handling version updates in the browser for optimal user experience. The article also highlights important considerations such as security implications, user communication for version updates, and the importance of thorough testing.

Step-by-Step Guide

Here's a breakdown of how to display your Angular application's version, combining best practices and addressing potential issues:

1. Accessing the Version from package.json

  • Direct Import (Not Recommended): While you could technically import package.json directly, this is generally discouraged. It can lead to bundling the entire file, increasing your application's size unnecessarily.

  • Environment Files (Recommended): A better approach is to leverage Angular's environment files. This allows you to manage different configurations for various environments (development, production, etc.).

    1. Create an environment.ts file:

      export const environment = {
  production: false,
  appVersion: require('../../package.json').version 
};

    2. Create an environment.prod.ts file (for production):

      export const environment = {
  production: true,
  appVersion: require('../../package.json').version
};

    3. Inject the Environment:

      import { Component } from '@angular/core';
import { environment } from '../environments/environment'; // Adjust path if needed

@Component({
  selector: 'app-root',
  template: `
    <p>App Version: {{ appVersion }}</p>
  `
})
export class AppComponent {
  appVersion = environment.appVersion;
}

2. Using a Build-Time Replacement

  • This method dynamically replaces a placeholder in your code with the actual version during the build process.

    1. Create a Placeholder: In your environment.ts files, use a placeholder:

      appVersion: 'APP_VERSION'

    2. Update Your Build Configuration: Modify your angular.json or build script to replace APP_VERSION with the value from package.json during the build. Here's an example using a custom webpack configuration:

      // webpack.config.js
const webpack = require('webpack');

module.exports = {
  // ... other configurations
  plugins: [
    new webpack.DefinePlugin({
      'APP_VERSION': JSON.stringify(require('./package.json').version)
    })
  ]
};

3. Handling Version Updates in the Browser

  • Cache Busting: If you want users to always get the latest version without manually clearing their cache, consider these techniques:

    • Appending Version to File Names: Modify your build process to include the version number in your script and CSS file names (e.g., main.1.2.3.js).
    • Using Hashes: Many build tools can generate unique hashes for file names, ensuring that browsers always fetch the newest assets.

Important Considerations:

  • Security: Be mindful of exposing sensitive version information in production. If your application has security vulnerabilities tied to specific versions, avoid displaying the full version publicly.
  • User Experience: Clearly communicate version updates to your users. Consider using a subtle notification or a dedicated "What's New" section.
  • Testing: Thoroughly test your version display logic across different browsers and environments to ensure it works as expected.

Code Example

This JavaScript code demonstrates how to display the version of an Angular application. It uses environment files to store the version information and replaces a placeholder with the actual version during the build process. The code includes instructions for setting up the project, modifying configuration files, and running the application. It also highlights the importance of testing the implementation in different environments.

This example demonstrates both methods: using environment files and build-time replacement.

1. Project Setup

Create a new Angular project (if you don't have one already):

ng new my-version-app
cd my-version-app

2. Environment Files (environment.ts)

// src/environments/environment.ts
export const environment = {
  production: false,
  appVersion: 'APP_VERSION' // Placeholder for build-time replacement
};

3. Environment Files (environment.prod.ts)

// src/environments/environment.prod.ts
export const environment = {
  production: true,
  appVersion: 'APP_VERSION' // Placeholder for build-time replacement
};

4. Component (app.component.ts)

// src/app/app.component.ts
import { Component } from '@angular/core';
import { environment } from '../environments/environment';

@Component({
  selector: 'app-root',
  template: `
    <h1>Welcome to {{ title }}!</h1>
    <p>App Version: {{ appVersion }}</p>
  `,
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'my-version-app';
  appVersion = environment.appVersion;
}

5. Modify angular.json for Build-Time Replacement

Add a custom webpack configuration to your angular.json file:

// angular.json
{
  "projects": {
    "my-version-app": {
      "architect": {
        "build": {
          "options": {
            // ... other options
          },
          "configurations": {
            "production": {
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ],
              "budgets": [
                // ...
              ]
            }
          }
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "configurations": {
            "production": {
              "browserTarget": "my-version-app:build:production"
            }
          }
        }
      }
    }
  },
  "version": 1
}

6. Modify package.json for Build Script

Add a build script to your package.json file:

// package.json
{
  "scripts": {
    "build": "ng build --prod",
    "start": "ng serve"
  }
}

7. Run the Application

npm run build // This will replace 'APP_VERSION' with the actual version
npm run start

Now, your Angular application will display the version number from your package.json file.

Important:

  • This example uses a simple placeholder replacement. For more complex scenarios or to handle cache busting, you might need to adjust the build process further.
  • Remember to test your implementation thoroughly, especially in different environments (development, production).

Additional Notes

Alternatives and Enhancements:

  • Using a Service: For more organized access to the version, consider creating an AppService and injecting it wherever needed. This centralizes version logic and makes it easier to manage.
  • Version Control System Integration: You can automate version updates during builds by fetching the latest tag or commit hash from your version control system (e.g., Git) and injecting it into your application.
  • Third-Party Libraries: Libraries like ngx-version can simplify the process of displaying and managing application versions.

Best Practices:

  • Semantic Versioning: Adhere to semantic versioning (SemVer) principles when updating your package.json version. This makes it clear to users and developers what types of changes each version introduces.
  • Environment-Specific Logic: You might want to display the version differently in development and production. For example, you could show a more prominent version indicator in development builds.
  • Error Handling: Implement error handling in case the version information cannot be retrieved from package.json or the build process encounters issues.

Security Considerations:

  • Minimize Exposure: Avoid exposing detailed version information in public-facing error messages or logs. This could provide attackers with clues about potential vulnerabilities.
  • Security by Obscurity: While not a primary security measure, consider obfuscating the version display to make it less obvious to casual observers.

User Experience (UX) Tips:

  • Subtle Display: Display the version number discreetly, such as in the footer or a dedicated "About" section. Avoid overwhelming users with this information.
  • Meaningful Updates: When communicating version updates, highlight new features, bug fixes, or important changes that are relevant to users.

Testing:

  • Automated Tests: Write unit tests to verify that your version display logic works correctly and that the version is updated as expected during builds.
  • Cross-Browser Compatibility: Test your version display across different browsers to ensure consistent behavior.

By following these additional notes, you can implement a robust and user-friendly solution for displaying and managing your Angular application's version.

Summary

Method Description Advantages Disadvantages
Direct Import from package.json Directly import the package.json file into your component. Simple to implement. Not recommended: Increases application size by bundling the entire package.json file.
Environment Files (Recommended) Store the version in Angular environment files (environment.ts, environment.prod.ts). Inject the environment into your component. Clean separation of configuration. Allows for different versions in different environments. Requires a bit more setup than direct import.
Build-Time Replacement Use a placeholder in your code and replace it with the actual version during the build process. Dynamically updates the version without bundling package.json. Requires modifying your build configuration.

Handling Version Updates in the Browser

  • Cache Busting:
    • Append the version number to file names (e.g., main.1.2.3.js).
    • Use hashes generated by build tools to ensure unique file names.

Important Considerations:

  • Security: Avoid exposing sensitive version information in production.
  • User Experience: Communicate version updates clearly to users.
  • Testing: Test version display logic across different browsers and environments.

Conclusion

By following the outlined strategies, developers can effectively manage and display application versions in their Angular projects, ensuring a transparent and user-friendly experience while upholding security and best practices.

References

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