TL;DR: Understanding JIT and AOT Compilation in Angular
Angular is a popular web framework for building Single Page Applications (SPAs) and Native Applications using modern technologies like TypeScript and RxJS. Angular supports two types of compilation: JIT (Just-in-Time) and AOT (Ahead-of-Time).
JIT vs. AOT: What’s the Difference?
The main difference between JIT and AOT in Angular is the way the compilation process takes place. JIT compilation compiles your app in the browser at runtime, while AOT compilation compiles your app at build time on the server. By default, Angular uses JIT compilation when running the ng build command (build only) or ng serve command (build and serve locally).
Advantages of AOT Compilation
Using AOT compilation offers several benefits:
- Faster rendering: AOT-compiled apps load and render faster, resulting in improved performance for end users.
- Fewer network requests: AOT compilation reduces the number of files that need to be fetched from the server, leading to faster load times.
- Smaller bundle size: AOT-compiled apps generate smaller bundle sizes, resulting in reduced bandwidth consumption and improved load times.
- Early error detection: AOT compilation detects template errors during the build process, allowing developers to catch and fix issues before deploying the app.
How to Compile an Angular App Using AOT
To build your app using AOT compilation, run the following command in the terminal:
ng build --prod --aot=true
This command tells Angular to perform an AOT compilation and generate a production-ready build of your app.
Advantages of JIT Compilation
JIT compilation also offers some advantages:
- No build required after code changes: JIT compilation dynamically compiles the changed files on the fly, eliminating the need for a complete rebuild of the app.
- Suitable for local development: JIT compilation is ideal for local development, as it allows for faster iterations and immediate feedback when making code changes.
Both JIT and AOT compilation have their own use cases, and the choice depends on the specific requirements of your project.