Angular

 

1. What are Standalone Components in Angular? Why did Angular introduce them?

Answer

  • Standalone components remove the need for NgModule.

  • Simplifies app structure and bootstrapping.

  • Enables better tree-shaking and faster startup.

In Angular, a Signal is a new reactive state primitive (introduced in Angular 16) used to store and track reactive data. It lets Angular automatically update the UI when the value changes — without needing RxJS or async pipes for simple state. Think of a signal like a special variable that “signals” Angular whenever its value changes.

2. What are Angular Signals?

Answer

  • Signals are a reactive primitive that tracks state change without Observables.

  • Similar to React signals/solid-js.

Example

const counter = signal(0);
counter.update(v => v + 1);

Why?

  • Predictable reactivity

  • No zone.js needed (future direction)

    Basic Example

    import { signal } from '@angular/core';

export class CounterComponent {
  count = signal(0);

  increment() {
    this.count.set(this.count() + 1);
  }
}

    In HTML:

    <p>Count: {{ count() }}</p>
<button (click)="increment()">Add</button>

    Notice we call count() to read the value.

Computed Signals

For derived values:

fullName = computed(() => `${this.firstName()} ${this.lastName()}`);

👂 Effect Signals

Runs automatically when signals change:

effect(() => {
  console.log("Count changed:", this.count());
});


SSR in Angular stands for Server-Side Rendering.
It means Angular renders the application on the server first (instead of only in the browser) and sends HTML to the client. After that, Angular runs normally in the browser.

How Angular SSR Works

Traditional SPA (no SSR):

  • Browser loads JS → JS builds HTML → User sees page

With SSR:

  1. Server generates HTML first

  2. Browser receives fully rendered HTML → fast display

  3. Angular bootstraps in browser and takes over (“hydration”)

🚀 How to enable SSR in Angular

Run:

ng add @angular/ssr

It adds server files and config.

Then start:

npm run dev:ssr

or build for production:

npm run build:ssr Hydration (in Angular and other web frameworks) is the process where the browser takes over a webpage that was pre-rendered on the server (SSR) and makes it fully interactive.
🧠 Why does Hydration exist?
With SSR (Server-Side Rendering):
  • Server sends ready-made HTML → page loads fast, good for SEO.
  • But HTML alone can’t respond to clicks, forms, navigation, etc.
Hydration connects that HTML to Angular's JavaScript, so the app becomes interactive without rebuilding the whole DOM.

npm run serve:ssr 🧠 Signals vs RxJS

SignalsRxJS
Simpler local component statePowerful async event streams
No subscriptions neededManual subscribe/unsubscribe
Great for UI data


Best for HTTP/websockets



11. What is the new Control Flow Syntax?

@if (loggedIn) {
   Welcome!
} @else {
   Please login
}

Replaces *ngIf, *ngFor sugar for readability/performancel.


14. What is Zone-less Angular?

  • Angular future direction → optional zone.js

  • Signals trigger UI updates manually

  • Higher performance


🔷 1. Standalone Components

Removes need for NgModules, simplifies app.

bootstrapApplication(AppComponent)

Benefits

  • Faster startup & tree-shaking

  • Less boilerplate

  • Better code-splitting

🔷 2. Signals

Next-gen change detection (future Zone-less Angular).

const count = signal(0);
count.update(v => v + 1);
SignalsObservables
StateStreams/events
Sync onlyAsync support
Simple UI stateEnterprise async flows

🔷 3. New Angular Control Flow (@if, @for)

@if(user()) { ... } @else { ... }

@for(item of list(); track $index) { ... }

Replaces *ngIf, *ngFor with faster syntax.

🔷 4. @defer – Deferred Views

Lazy renders UI sections based on triggers.

@defer (on idle) {
  <heavy-dashboard />
} @loading { Loading... }

🔷 5. Functional Routing

export const routes = [
  { path: 'home', loadComponent: () => import('./home.component') }
];

🔷 6. Typed Reactive Forms

form = new FormGroup({
  name: new FormControl<string>(''),
});

Compile-time safety ✅

🔷 7. SSR + Hydration

SEO + performance

ng add @angular/ssr

🔷 8. Zones vs Zone-less

Zone-less + Signals = future Angular engine.

Benefits:

  • Faster rendering

  • More predictable reactivity

🔷 9. RxJS Latest Patterns

Use:

  • switchMap, combineLatest, catchError

  • takeUntilDestroyed()

  • Replay/cache heavy API calls

Avoid manual subscriptions unless needed.




Comments

Post a Comment

Popular posts from this blog

Archunit test

  ArchUnit  integrates nicely with the  JUnit  test framework, and so, they are typically used together.  All we have to do is add the  archunit-junit 5  dependency to match our  JUnit  version: < dependency > < groupId > com.tngtech.archunit </ groupId > < artifactId > archunit-junit5 </ artifactId > < version > 0.14.1 </ version > < scope > test </ scope > </ dependency > Step 1: The first step is to create a set of Java classes that will be checked for rules violations . We do this by instantiating the  ClassFileImporter  class and then using one of its  importXXX()  methods: JavaClasses jc = new ClassFileImporter () .importPackages( "com.baeldung.archunit.smurfs" ); Step 2:  Let’s try to implement the first rule defined above using this API. We’ll use the  classes()  method as our anchor and add additional constraints ...
Read more

Hexagonal Architecture

Image
  Hexagonal architecture is a model of  designing software applications around domain logic  to isolate it from external factors. The domain logic is specified in a business core, which we’ll call the inside part, with the rest being outside parts.  Access to domain logic from the outside is available through  ports  and  adapters .  here we divide our application into three layers:  application (outside), domain (inside), and infrastructure (outside): Through  the application layer, the user or any other program interacts  with the application. This area should contain things like user interfaces, RESTful controllers, and JSON serialization libraries. It includes anything  that exposes entry to our application, and orchestrates the execution of domain logic. In the domain layer, we keep the code that touches and implements business logic . This is the core of our application. This layer should be isolated from both the applica...
Read more

visitor design pattern

Image
  The Visitor design pattern is a  behavioral pattern  that allows you to add new operations to a group of related classes without modifying their structures. Real-World Example of Visitor Design Pattern A simple example of the Visitor design pattern is in an online shopping cart. Imagine you have different items like books, electronics, and clothing. Each item can accept a visitor that performs actions like calculating the total price or applying discounts. This way, you can add new features without changing the item classes, making the system easier to maintain and update. UML Class Diagram of Visitor design pattern Components of Visitor Design Pattern The Visitor design pattern consists of several key components that work together to enable its functionality. Here’s a breakdown of these components: Visitor Interface : This interface declares a visit method for each type of element in the object structure. Each method is designed to handle a specific element type. Concr...
Read more