Angular Control Flow

Control flow directives (@if, @for, @switch) render branches, lists, and cases in templates and replace the legacy *ngIf/*ngFor/[ngSwitch] for new code.

Control Flow Essentials

• @if: Conditional blocks with optional else if/else.
• @for: Loops with track for stable identity and optional @empty for empty states.
• @switch: Selects and renders a matching case.
• Preferred for new code in Angular 17+; legacy *ngIf/*ngFor/[ngSwitch] remain supported.

@if (score > 90) { <p>A</p> } @else if (score > 75) { <p>B</p> } @else { <p>C</p> }

<ul>
  @for (it of items; track it.id) { <li>{{ it.label }}</li> } @empty { <li>No items</li> }
</ul>

@switch (status) {
  @case ('pending') { <p>Pending</p> }
  @case ('done') { <p>Done</p> }
  @default { <p>Unknown</p> }
}

Code explained

• @if ... @else: Branches to render different blocks based on a condition.
• @for (...; track ...): Iterates and uses track to keep stable identities for DOM reuse.
• @switch/@case/@default: Selects and renders a matching case.

Control Flow Basics

Toggle content with @if ...; else.

Iterate with @for and add a track expression for stable DOM updates.

@if (show) { <p>Visible</p> } @else { <p>Hidden</p> }

@for (item of items; track item) { <li>{{ item }}</li> }

Example

Toggle content with @if, and render lists with @for using a track expression:

import { bootstrapApplication } from '@angular/platform-browser';
import { Component, signal } from '@angular/core';

@Component({
  selector: 'app-root',
  standalone: true,
  template: `
    <h3>Control Flow</h3>
    <button (click)="show.set(!show())">Toggle</button>
    <button (click)="items.set([])">Clear</button>
    <button (click)="reset()">Reset</button>

    @if (show()) {
      <p>Visible</p>
    } @else {
      <p>Hidden</p>
    }

    <ul>
      @for (item of items(); track item) {
        <li>{{ item }}</li>
      } @empty {
        <li>No items</li>
      }
    </ul>
  `
})
export class App {
  show = signal(true);
  items = signal(['One','Two','Three']);
  reset() { this.items.set(['One','Two','Three']); }
}

bootstrapApplication(App);

<app-root></app-root>

Example explained

• @if ... @else: Toggles the paragraph based on the show() signal.
• @for ... track item: Renders the list from the items() signal and preserves DOM with track.
• @empty: Displays a fallback when the list is empty.
• Signals: Buttons update show and items, which re-render the view.