What is AOT and JIT , Ivy and V8 how work together in angular ?

How Many Compilation Mode in Angular ?

AOT (Ahead-of-Time) and JIT (Just-In-Time) are two different compilation modes used in Angular to convert your application’s TypeScript code and templates into executable JavaScript code. Each mode has its own characteristics and benefits:

1. AOT (Ahead-of-Time) Compilation:
2. AOT compilation is a process in which your Angular application’s code is compiled and optimized before it’s delivered to the browser.
3. During AOT compilation, Angular’s templates are also compiled ahead of time into JavaScript code.

Benefits of AOT:

1. Faster Load Times: AOT-compiled applications tend to load faster because the browser doesn’t need to spend time compiling templates. Templates are already in JavaScript form.
2. Smaller Bundle Sizes: AOT eliminates the Angular compiler and reduces the size of the final bundle, leading to smaller file sizes and improved performance.
3. Template Type Checking: AOT includes enhanced template type checking, catching potential errors during compilation.
4. Better Security: Since templates are precompiled, there’s a reduced risk of template-related security vulnerabilities.

JIT (Just-In-Time) Compilation:

1. JIT compilation is a process where your Angular application’s code is compiled in the browser at runtime, just before it’s executed.
2. During JIT compilation, the Angular templates are compiled in the browser, which can lead to slower initial loading times.

Benefits of JIT:

1. Development Convenience: JIT compilation simplifies the development process, as you can make changes to your code and see them reflected immediately without needing to recompile.
2. Dynamically Generated Templates: JIT allows the generation of dynamic templates, such as those created based on user input or data fetched from APIs.
3. Better for Rapid Prototyping: In development or rapid prototyping scenarios, JIT’s quicker turnaround time can be advantageous.

In summary, AOT (Ahead-of-Time) and JIT (Just-In-Time) are two compilation modes in Angular that offer different trade-offs in terms of performance, bundle size, development convenience, and security.

AOT is often preferred for production environments because of its advantages in terms of load times, bundle size, and template type checking. It’s the default compilation mode for Angular applications.

JIT, on the other hand, is useful during development due to its rapid iteration capabilities. Developers can make code changes and immediately see the results without the need for a separate build step. However, JIT-compiled applications might have slightly slower initial load times and larger bundle sizes compared to AOT-compiled applications.

What is Ivy in Angular ?

Ivy is the codename for the next-generation compilation and rendering pipeline of the Angular framework. It represents a significant advancement in how Angular applications are compiled, rendered, and executed. Ivy was developed to address various limitations of the previous rendering engine (known as View Engine) and to bring several new benefits to Angular developers. Here are the key aspects of Ivy:

1. Smaller bundle size with tree shaking process(remove unused code).
2. Improved debugging and error info instead of zone.js trace out particular component line or template name.
3. Using incremental Dom instead of Virtual Dom for change comparison.
4. Enhanced Type checking instead of runtime check.
5. Angular Ivy:Angular Ivy is the next-generation compilation and rendering engine for Angular applications. It’s responsible for transforming your TypeScript code and templates into optimized JavaScript code that can be executed by browsers. Ivy provides improved performance, better debugging capabilities, enhanced type checking, and smaller bundle sizes compared to the previous View Engine. It introduces a more efficient rendering and change detection mechanism, which helps reduce the overhead associated with updating the UI in response to changes in data.
6. V8 Engine:The V8 engine is an open-source JavaScript engine developed by Google. It’s the engine that powers modern browsers like Chrome, and it’s responsible for executing JavaScript code.V8 compiles JavaScript code into machine code and handles various optimizations to ensure efficient execution. Angular applications, like other web applications, rely on the V8 engine to execute the JavaScript code generated by Angular’s compilation process.

How Ivy and V8 Work Together:

1. Compilation Phase:During the compilation phase, Ivy takes your Angular application’s TypeScript code and templates and transforms them into optimized JavaScript code.This compiled JavaScript code includes the application logic, templates, and other Angular-specific constructs.
2. Execution Phase:Once the Angular application is compiled into JavaScript, the resulting code is executed by the JavaScript engine, which is often the V8 engine in modern browsers. The V8 engine compiles the JavaScript code further into machine code and executes it. During execution, the V8 engine interacts with the browser’s Document Object Model (DOM) to render the UI based on the generated code.
3. Change Detection and Rendering:Ivy’s efficient change detection and rendering mechanisms ensure that the application’s UI updates are reflected accurately and efficiently in the browser. When data changes in the application, Ivy’s change detection system identifies the changes and triggers the necessary updates to the DOM. The V8 engine plays a role in executing the change detection and rendering logic, ensuring that the updated UI is displayed to the user.

In summary, Angular Ivy and the V8 engine work together to enable the development and execution of Angular applications. Ivy is responsible for compiling and optimizing the application code, while the V8 engine executes the generated JavaScript code and handles the rendering and updating of the application’s user interface in the browser.

Angular Compilation More Details

Compilation in Angular