# Build & Optimization (Angular)

> Production builds, AOT compilation, tree shaking, lazy loading, bundle optimization, source maps, budgets

- 20 interview questions
- Mid-Level
- [Interview Questions: Angular](https://sharpskill.dev/en/technologies/angular/interview-questions.md)

## 1. What is AOT compilation in Angular?

**Answer**

AOT (Ahead-of-Time) compilation transforms Angular code and templates into optimized JavaScript during the build phase, before deployment. This reduces bundle size as the Angular compiler is not included, improves loading performance, and detects template errors earlier. Since Angular 9, AOT is enabled by default for all builds.

## 2. What is the main advantage of AOT over JIT compilation?

**Answer**

AOT produces smaller bundles because the Angular compiler (about 1MB) is excluded from the final bundle, unlike JIT which requires the compiler in the browser. AOT also improves loading time by eliminating client-side compilation, detects template errors earlier, and improves security by pre-compiling templates.

## 3. How to enable AOT compilation in an ng build command?

**Answer**

Since Angular 9, AOT is the default compilation for all environments. For a production build, using ng build --configuration production automatically enables AOT. The --aot flag exists but is redundant as AOT is now always active unless explicitly configured otherwise in angular.json.

## 17 more questions available

- Which configuration in angular.json enables optimizations for a production build?
- What is tree shaking in Angular?

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## Other Angular interview topics

- [TypeScript Basics](https://sharpskill.dev/en/technologies/angular/interview-questions/typescript-basics.md): 25 questions, Junior
- [TypeScript Advanced](https://sharpskill.dev/en/technologies/angular/interview-questions/typescript-advanced.md): 20 questions, Junior
- [Angular Fundamentals](https://sharpskill.dev/en/technologies/angular/interview-questions/angular-fundamentals.md): 20 questions, Junior
- [Components & Lifecycle](https://sharpskill.dev/en/technologies/angular/interview-questions/components-lifecycle.md): 20 questions, Junior
- [Services & Dependency Injection](https://sharpskill.dev/en/technologies/angular/interview-questions/services-dependency-injection.md): 20 questions, Junior
- [Angular Modules Organization](https://sharpskill.dev/en/technologies/angular/interview-questions/modules-organization.md): 22 questions, Mid-Level
- [Angular CLI](https://sharpskill.dev/en/technologies/angular/interview-questions/angular-cli.md): 18 questions, Junior
- [Directives & Pipes](https://sharpskill.dev/en/technologies/angular/interview-questions/directives-pipes.md): 22 questions, Mid-Level
- [Routing & Navigation](https://sharpskill.dev/en/technologies/angular/interview-questions/routing-navigation.md): 24 questions, Mid-Level
- [Reactive Forms](https://sharpskill.dev/en/technologies/angular/interview-questions/forms-reactive.md): 26 questions, Mid-Level
- [Template-driven Forms](https://sharpskill.dev/en/technologies/angular/interview-questions/forms-template-driven.md): 16 questions, Mid-Level
- [RxJS Fundamentals](https://sharpskill.dev/en/technologies/angular/interview-questions/rxjs-fundamentals.md): 22 questions, Mid-Level
- [RxJS Operators](https://sharpskill.dev/en/technologies/angular/interview-questions/rxjs-operators.md): 24 questions, Mid-Level
- [HttpClient & API Calls](https://sharpskill.dev/en/technologies/angular/interview-questions/http-client.md): 22 questions, Mid-Level
- [Basic State Management](https://sharpskill.dev/en/technologies/angular/interview-questions/state-management-basics.md): 20 questions, Mid-Level
- [Change Detection](https://sharpskill.dev/en/technologies/angular/interview-questions/change-detection.md): 20 questions, Mid-Level
- [Angular Signals](https://sharpskill.dev/en/technologies/angular/interview-questions/angular-signals.md): 20 questions, Mid-Level
- [Standalone Components](https://sharpskill.dev/en/technologies/angular/interview-questions/standalone-components.md): 18 questions, Mid-Level
- [Angular Unit Testing](https://sharpskill.dev/en/technologies/angular/interview-questions/testing-unit.md): 22 questions, Mid-Level
- [End-to-End Testing](https://sharpskill.dev/en/technologies/angular/interview-questions/testing-e2e.md): 18 questions, Mid-Level
- [NgRx Fundamentals](https://sharpskill.dev/en/technologies/angular/interview-questions/ngrx-fundamentals.md): 24 questions, Senior
- [NgRx Advanced](https://sharpskill.dev/en/technologies/angular/interview-questions/ngrx-advanced.md): 24 questions, Senior
- [Angular Architecture](https://sharpskill.dev/en/technologies/angular/interview-questions/angular-architecture.md): 22 questions, Senior
- [Performance Optimization](https://sharpskill.dev/en/technologies/angular/interview-questions/performance-optimization.md): 22 questions, Senior
- [Security & Best Practices](https://sharpskill.dev/en/technologies/angular/interview-questions/security-best-practices.md): 20 questions, Senior
- [Advanced RxJS Patterns](https://sharpskill.dev/en/technologies/angular/interview-questions/advanced-rxjs-patterns.md): 22 questions, Senior
- [Angular Universal & SSR](https://sharpskill.dev/en/technologies/angular/interview-questions/angular-universal-ssr.md): 20 questions, Senior
- [Angular Micro-frontends](https://sharpskill.dev/en/technologies/angular/interview-questions/micro-frontends-angular.md): 20 questions, Senior

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