Understanding the 'ng build --prod' Command in Angular

The 'ng build' command is a crucial part of the Angular framework, and more specifically, the Angular CLI or Command Line Interface. Its principal function is to build your Angular application, taking your source files and compiling them into an output directory.

However, when the '--prod' flag is appended to this command - creating 'ng build --prod' - the command takes on an additional function. This revised command is used to build the Angular application specifically for a production environment, with various optimizations included.

Building for Production: What Does It Mean?

In the context of web development, a 'production' environment refers to the final output environment where your application will be available to the end-users. This is in contrast to the 'development' environment, which is primarily utilized for testing and development purposes.

Building for production specifically involves additional steps and optimizations that are aligned to a production setting. These additional steps might involve minification (to reduce the size of the application), uglification (to mangle the names of functions and variables to shorter forms), and dead code elimination.

When you run the 'ng build --prod' command, Angular runs a production build of your application with the Angular ahead-of-time (AOT) compiler. The AOT compiler converts your Angular HTML and TypeScript code into efficient JavaScript code during the build phase before the browser downloads and runs that code.

Practical Application of 'ng build --prod'

So, when should you use the 'ng build --prod' command? This should be utilized when you're ready to deploy your Angular application and make it public. Before you do so, you'd run this command to create an optimized version of your app in the 'dist/' output directory. These optimized files are the ones you'd upload to your server or hosting service when deploying the app.

Best Practices around Building for Production

Here are a few best practices to consider when utilizing 'ng build --prod':

1. Always test your application with 'ng build --prod' before deploying it. It may behave differently from the development mode due to the additional optimizations that were applied.
2. Remember that building for production includes both minification and uglification. These processes can make debugging the production code challenging since the function and variable names would have been shortened and the code would have been compressed. As such, ensure that all debugging has been done in the development phase.
3. Make use of the Angular CLI's environment-specific configurations with the 'ng build' command to inject and use different values in the production and the development modes.

In conclusion, the 'ng build --prod' command is instrumental when deploying an Angular application. The command ensures that you're putting out an optimized, efficient, and fast-loading app, providing the best possible user experience.