Angular 18 in VSCode devcontainer renders blank page on ng serve: A Comprehensive Troubleshooting Guide

If you’re reading this, chances are you’ve encountered the frustrating issue of Angular 18 in a VSCode devcontainer rendering a blank page on `ng serve`. Don’t worry, you’re not alone! This guide will walk you through a series of steps to help you troubleshoot and resolve this pesky problem.

Prerequisites

Before we dive into the troubleshooting process, make sure you’ve got the following set up:

• VSCode installed on your machine with the Dev Container extension.
• A devcontainer.json file configured for Angular 18.
• The Angular CLI installed globally or locally in your project.

Step 1: Check Logs

The first step in troubleshooting is to examine the logs. In your VSCode terminal, run the following command:

ng serve --verbose

This command will start the development server with verbose logging enabled. Observe the output carefully, looking for any error messages or warnings that might indicate the root cause of the issue.

Common Log Issues

Keep an eye out for the following common log issues:

• Error: Cannot find module '@angular-devkit/build-angular': This error usually indicates a mismatch between the versions of Angular and the Angular CLI. Ensure you’re using compatible versions.
• TypeError: Cannot read property 'length' of undefined: This error often occurs when there’s an issue with the Angular project configuration. Check your `angular.json` file for any syntax errors or incorrect settings.
• Module build failed: Error: Cannot find module 'webpack': This error typically indicates a problem with the Webpack configuration. Verify that your `webpack.config.js` file is correctly configured.

Step 2: Check Config Files

Config files can be a common source of errors. Let’s review the most critical ones:

angular.json

Open your `angular.json` file and verify the following:

{
  "projects": {
    "your-project": {
      ...
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            ...
            "outputPath": "dist/your-project",
            ...
          },
          ...
        },
        ...
      }
    }
  }
}

Ensure that the `builder` property is set to `@angular-devkit/build-angular:browser` and the `outputPath` is correctly configured.

devcontainer.json

Review your `devcontainer.json` file to ensure it’s configured correctly:

{
  "name": "Angular 18",
  "image": "mcr.microsoft.com/devcontainers/typescript:1-typescript-4.2",
  "ports": [4200],
  "command": "bash",
  "mounts": [
    "source=${localWorkspaceFolder}/your-project,target=/app,type=bind,consistency=cached"
  ],
  "settings": {
    "terminal.integrated.shell.linux": "/bin/bash"
  }
}

Verify that the `image` property is set to a compatible version, and the `ports` and `mounts` configurations are correct.

Step 3: Check Dependencies

Ensure that all dependencies are correctly installed and up-to-date:

npm install --save-dev @angular-devkit/build-angular

Run the above command to install the `@angular-devkit/build-angular` package, which is required for Angular 18.

Step 4: Rebuild and Serve

Try rebuilding your Angular project and serving it again:

ng build --configuration=development && ng serve --verbose

This command will rebuild your project using the `development` configuration and then serve it with verbose logging enabled. If the issue persists, try adjusting the `configuration` option to `production` or another setting that suits your needs.

Step 5: Debug with Remote Debugging

If the above steps don’t resolve the issue, let’s try using remote debugging:

Enable Remote Debugging

In your `launch.json` file, add the following configuration:

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Debug Angular",
      "program": "${workspaceFolder}/your-project",
      "outFiles": ["${workspaceFolder}/dist/**/*.js"],
      "preLaunchCommand": "npm run build",
      "internalConsoleOptions": "neverOpen"
    }
  ]
}

This configuration enables remote debugging for your Angular project.

Start Debugging

Press F5 or click the “Debug” button in VSCode to start the debugging process. This will launch the Angular development server and attach the debugger to it.

Once the debugger is attached, you can set breakpoints, inspect variables, and step through your code to identify the root cause of the issue.

Step 6: Cleanup and Restart

If all else fails, try cleaning up your project and restarting the devcontainer:

npm run clean && npm install && devcontainer restart

This command will remove any existing build artifacts, reinstall dependencies, and restart the devcontainer.

Conclusion

By following this comprehensive guide, you should be able to troubleshoot and resolve the issue of Angular 18 in a VSCode devcontainer rendering a blank page on `ng serve`. Remember to carefully review your config files, dependencies, and build process to ensure everything is correctly set up. If you’re still stuck, feel free to seek help from the Angular community or online forums.

Step	Description
1	Check logs for errors and warnings
2	Verify angular.json and devcontainer.json configurations
3	Check and update dependencies
4	Rebuild and serve the project
5	Debug the project using remote debugging
6	Cleanup and restart the devcontainer

Remember, troubleshooting can be a process of elimination. Be patient, and don’t hesitate to reach out for help if you need it. Good luck!

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