By the culmination of this tutorial, you will:
Understand the Angular Compiler's mechanisms and its critical role in Angular applications.
Customize the compiler to achieve enhanced performance metrics and smaller bundle footprints.
Employ advanced techniques like AOT Compilation and Tree shaking to further refine and improve the application's runtime efficiency.
To gain the most from this tutorial, participants should possess:
A comprehensive understanding of Angular and its foundational mechanics.
Experience in building and deploying Angular applications.
Familiarity with basic compiler concepts and Angular CLI.
An eagerness to delve deep and uncover the potential behind Angular's compilation magic.
A Deep Dive into the Angular Compiler
Anatomy of the Angular Compiler
Analysis: In this phase, the compiler analyzes the metadata about your components, directives, and modules. It validates the metadata and checks for errors.
Parsing: The compiler parses the TypeScript files into an Abstract Syntax Tree (AST).
Type Checking: The compiler uses TypeScript’s type checker to validate the types in your code.
Optimization: The compiler applies various optimizations to the generated code to make it more efficient.
Understanding Just-in-Time (JIT) vs. Ahead of Time (AOT) Compilation
Angular provides two compilation modes: Just-in-Time (JIT) and Ahead-of-Time (AOT).
Just-in-Time (JIT) Compilation: In JIT mode, the compilation happens at runtime, in the browser. This means that the compiler is included in your application bundle and runs when your application loads in the browser.
Ahead-of-Time (AOT) Compilation: In AOT mode, the compilation happens at build time, on your development machine. This means that the compiler is not included in your application bundle, resulting in smaller bundle sizes and faster load times.
While JIT compilation can be useful during development due to its fast rebuild times, AOT compilation is recommended for production builds due to its performance benefits.
Importance of Compilation in Angular
Why is Compilation Critical for Angular Applications?
Type Safety: The Angular compiler uses TypeScript’s powerful type system during the compilation process to catch a wide range of errors before they make it to production. This leads to more robust code and can save you from subtle bugs.
Framework Features: Many of Angular’s powerful features, such as decorators, dependency injection, and data binding, are implemented as part of the compilation process.
Performance, Bundle Size, and Startup Implications
The way you choose to compile your Angular application can have significant implications on its performance, bundle size, and startup time:
Just-in-Time (JIT) Compilation: In JIT mode, the Angular compiler is included in your application bundle and runs in the browser when your application starts. This leads to larger bundle sizes and slower startup times because the browser must download and parse the compiler code and compile the application before it can be run. However, JIT compilation can be faster for development builds because it only compiles what’s needed.
In general, while JIT compilation can be useful during development due to its fast rebuild times, AOT compilation is recommended for production builds due to its performance benefits.
Enhancing Performance with Ahead of Time (AOT) Compilation
What is AOT Compilation and Why is it Preferred?
AOT compilation is preferred for a few reasons:
Template Errors: During AOT compilation, templates are checked for errors. This means you can catch and fix any template errors during the build process before users see them.
Reduced Load: Since Angular’s compiler is not shipped with the AOT compiled application, users don’t have to download it. This results in a smaller application payload size, leading to faster download times.
Setting up AOT Compilation for an Angular Application
Setting up AOT compilation in an Angular application is straightforward. If you’re using Angular CLI, AOT compilation is enabled by default when you run the ng build --prod command.
However, if you want to enable AOT during development, you can add the --aot flag to the ng serve or ng build commands like so:
This post is for paying subscribers only
Sign up now and upgrade your account to read the post and get access to the full library of posts for paying subscribers only.