Jassif Team Institution

Angular Router

Router URLs-ஐ views-க்கு map செய்து உங்கள் app-ல் users navigate செய்ய அனுமதிக்கிறது.

import { provideRouter, withHashLocation, RouterOutlet, RouterLink } from '@angular/router';

const routes = [
  { path: '', component: Home },
  { path: 'about', component: About }
];

bootstrapApplication(App, {
  providers: [provideRouter(routes, withHashLocation())]
});

// Template
// <a routerLink="/about">About</a>
// <router-outlet></router-outlet>

Router Basics

Paths-ஐ components-க்கு map செய்ய routes array define செய்யவும்.

provideRouter() உடன் routes provide செய்யவும் (sandboxes-க்கு withHashLocation() பயன்படுத்தவும்).

Navigation-க்கு routerLink பயன்படுத்தவும் மற்றும் views render செய்ய RouterOutlet பயன்படுத்தவும்.

const routes = [ { path: '', component: Home }, { path: 'about', component: About } ];
// template
// <a routerLink="/about">About</a>
// <router-outlet></router-outlet>

Example

import { bootstrapApplication } from '@angular/platform-browser';
import { Component } from '@angular/core';
import { provideRouter, RouterOutlet, RouterLink, withHashLocation } from '@angular/router';

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet, RouterLink],
  template: `
    <h3>Router</h3>
    <nav>
      <a routerLink="/">Home</a> |
      <a routerLink="/about">About</a>
    </nav>
    <router-outlet></router-outlet>
  `
})
export class App {}

@Component({
  standalone: true,
  template: `<p>Home works!</p>`
})
export class Home {}

@Component({
  standalone: true,
  template: `<p>About works!</p>`
})
export class About {}

const routes = [
  { path: '', component: Home },
  { path: 'about', component: About }
];

bootstrapApplication(App, {
  providers: [provideRouter(routes, withHashLocation())]
});

Router Params

Paths-ல் variables capture செய்ய :id உடன் (e.g., /product/42).

ActivatedRoute மூலம் அவற்றை read செய்யவும் (snapshot அல்லது paramMap observable).

{ path: 'product/:id', component: Product }
// class Product {
//  id = '';
//  route = inject(ActivatedRoute);
//  ngOnInit() { this.id = this.route.snapshot.paramMap.get('id') ?? ''; }
// }

Example

import { bootstrapApplication } from '@angular/platform-browser';
import { Component, OnInit, inject } from '@angular/core';
import { provideRouter, RouterOutlet, RouterLink, RouterLinkActive, ActivatedRoute, withHashLocation } from '@angular/router';

@Component({
  selector: 'home-cmp',
  standalone: true,
  template: `<p>Home works!</p>`
})
export class Home {}

@Component({
  selector: 'product-cmp',
  standalone: true,
  template: `<p>Product ID: {{ id }}</p>`
})
export class Product implements OnInit {
  id = '';
  private route = inject(ActivatedRoute);
  ngOnInit() {
    this.id = this.route.snapshot.paramMap.get('id') ?? '';
  }
}

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet, RouterLink, RouterLinkActive],
  template: `
    <h3>Router Params</h3>
    <nav>
      <a routerLink="/">Home</a> |
      <a routerLink="/product/1" routerLinkActive="active">Product 1</a> |
      <a routerLink="/product/2" routerLinkActive="active">Product 2</a>
    </nav>
    <router-outlet></router-outlet>
  `,
  styles: [`nav a { margin-right: 6px; } .active { font-weight: bold; }`]
})
export class App {}

const routes = [
  { path: '', component: Home },
  { path: 'product/:id', component: Product }
];

bootstrapApplication(App, {
  providers: [provideRouter(routes, withHashLocation())]
});

Active Links

Link match ஆகும் போது classes toggle செய்ய routerLinkActive பயன்படுத்தவும்.

Root links போன்ற /-க்கு { exact: true } set செய்யவும்.

<a routerLink="/" routerLinkActive="active" [routerLinkActiveOptions]="{ exact: true }">Home</a>
<a routerLink="/about" routerLinkActive="active">About</a>

Example

import { bootstrapApplication } from '@angular/platform-browser';
import { Component } from '@angular/core';
import { provideRouter, RouterOutlet, RouterLink, RouterLinkActive, withHashLocation } from '@angular/router';

@Component({
  standalone: true,
  template: `<p>Home works!</p>`
})
export class Home {}

@Component({
  standalone: true,
  template: `<p>About works!</p>`
})
export class About {}

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet, RouterLink, RouterLinkActive],
  styles: [`
    nav a { margin-right: 8px; text-decoration: none; }
    .active { font-weight: 600; color: seagreen; }
  `],
  template: `
    <h3>Active Links (routerLinkActive)</h3>
    <nav>
      <a routerLink="/" routerLinkActive="active" [routerLinkActiveOptions]="{ exact: true }">Home</a>
      <a routerLink="/about" routerLinkActive="active">About</a>
    </nav>
    <router-outlet></router-outlet>
  `
})
export class App {}

const routes = [
  { path: '', component: Home },
  { path: 'about', component: About }
];

bootstrapApplication(App, {
  providers: [provideRouter(routes, withHashLocation())]
});

Lazy-loaded Component

Navigation வரை code loading defer செய்ய loadComponent அல்லது loadChildren பயன்படுத்தவும்.

Bundles splitting செய்வதன் மூலம் initial load time improve செய்கிறது.

{ path: 'about', loadComponent: () => import('./about').then(m => m.About) }

Example

import { bootstrapApplication } from '@angular/platform-browser';
import { Component } from '@angular/core';
import { provideRouter, RouterOutlet, RouterLink, withHashLocation } from '@angular/router';

@Component({
  standalone: true,
  template: `<p>Home works!</p>`
})
export class Home {}

@Component({
  standalone: true,
  template: `<p>About works (lazy)!</p>`
})
export class About {}

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet, RouterLink],
  styles: [`
    nav a { margin-right: 8px; text-decoration: none; }
  `],
  template: `
    <h3>Lazy-loaded Component (loadComponent)</h3>
    <nav>
      <a routerLink="/">Home</a>
      <a routerLink="/about">About (lazy)</a>
    </nav>
    <router-outlet></router-outlet>
  `
})
export class App {}

const routes = [
  { path: '', component: Home },
  // Use Promise.resolve to simulate lazy loading without dynamic imports
  { path: 'about', loadComponent: () => Promise.resolve(About) }
];

bootstrapApplication(App, {
  providers: [provideRouter(routes, withHashLocation())]
});

Route Guard (canActivate)

Guards navigation allowed என்பதை தீர்மானிக்கின்றன.

true (allow), false/UrlTree (block/redirect), அல்லது async equivalents return செய்யவும்.

export const authGuard = () => isLoggedIn ? true : inject(Router).createUrlTree(['/']);
{ path: 'protected', component: Protected, canActivate: [authGuard] }

Example

import { bootstrapApplication } from '@angular/platform-browser';
import { Component, inject } from '@angular/core';
import { provideRouter, RouterOutlet, RouterLink, withHashLocation, Router } from '@angular/router';

let loggedIn = false;

export const authGuard = () => {
  if (loggedIn) return true;
  const router = inject(Router);
  return router.createUrlTree(['/']);
};

@Component({
  standalone: true,
  template: `<p>Home (public).</p>
<p>Login to access protected route.</p>`
})
export class Home {}

@Component({
  standalone: true,
  template: `<p>Protected works! You are logged in.</p>`
})
export class Protected {}

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet, RouterLink],
  styles: [`
    nav a { margin-right: 8px; text-decoration: none; }
    .status { margin-left: 8px; font-weight: 600; }
  `],
  template: `
    <h3>Route Guard (canActivate)</h3>
    <div class="toolbar">
      <button (click)="toggle()">{{ loggedIn ? 'Log out' : 'Log in' }}</button>
      <span class="status">Status: {{ loggedIn ? 'Logged in' : 'Logged out' }}</span>
    </div>
    <nav>
      <a routerLink="/">Home</a>
      <a routerLink="/protected">Protected</a>
    </nav>
    <router-outlet></router-outlet>
  `
})
export class App {
  get loggedIn() { return loggedIn; }
  toggle() { loggedIn = !loggedIn; }
}

const routes = [
  { path: '', component: Home },
  { path: 'protected', component: Protected, canActivate: [authGuard] }
];

bootstrapApplication(App, {
  providers: [provideRouter(routes, withHashLocation())]
});

Exercise