Angular Templates

Templates are the HTML that a component renders.

Templates combine plain HTML with Angular template syntax to show data and react to user events.

Components, Templates, and Selectors

• A component is a class that controls a view (its template).
• Each component has a selector (e.g., app-root) that you place in HTML.
• The root component renders inside index.html's <app-root>.

How templates work

1. Initial render: Angular creates the component and processes the template, wiring bindings between the DOM and component fields.
2. Change detection: On user events, timers, or async work, Angular re-evaluates template expressions and updates only what changed.
3. Directives: Create/destroy embedded views (DOM fragments) based on state.
4. Binding flow: Interpolation/Property binding push data to the view. Event binding captures browser events back to the component.

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

@Component({
  selector: 'app-root',
  standalone: true,
  template: `
    <h3>Hello {{ name }}</h3>
    <button (click)="name = 'Angular'">Reset</button>
  `
})
export class App {
  name = 'World';
}

bootstrapApplication(App);

<app-root></app-root>

Example explained

• {{ name }}: Interpolation reads the name field and inserts it as text.
• (click): Event binding updates the component state when the button is clicked.

Template Essentials

Key concepts:

• Templates are the HTML that Angular renders for a component.
• Bindings: interpolation {{ ... }}, property [prop], and event (event).
• Template refs: local names like #box to reference elements or directives.
• Structural directives (*ngIf, *ngFor) change the DOM layout.

<p>Hello {{ name }}</p>
<img [src]="url" (error)="onMissing()">
<input #box (input)="save(box.value)">
<li *ngFor="let item of items; index as i">{{ i }}. {{ item }}</li>

Code explained

• {{ name }}: Interpolation for text.
• [src]: Property binding to set an element property.
• (error): Event binding to react to the image error event.
• #box: Template reference variable; box.value reads the current input value.
• *ngFor ... index as i: Structural directive to loop with the zero-based index.

Templates Overview

Explore templates step by step in these next chapters:

• Interpolation - show values with {{ ... }}.
• Template Reference Variables - use #var to reference elements.
• Null-Safe Navigation (?.) - read optional values safely.
• Structural Directives: Micro-syntax - the * shorthand.
• ngTemplateOutlet - render a template by reference.
• Template Statements and $event - handle events and inputs.
• Alias with as in *ngIf - create local aliases.
• Pipes in Templates (|) - format and transform values.
• Attribute Binding with attr. - bind to HTML attributes.
• TrackBy with *ngFor - keep lists fast and stable.