Angular’s Signal Revolution: Effortless Change Detection Explained — Unveiling the Inner Workings

<p>Angular&rsquo;s signals bring a host of benefits to the table, one of which is their ability to seamlessly integrate with templates and &ldquo;automate&rdquo; change detection. This automation means that a component configured with the&nbsp;<code>OnPush</code>&nbsp;change detection strategy will be rechecked during the next change detection cycle, sparing developers from manually injecting&nbsp;<code>ChangeDetectorRef</code>&nbsp;and invoking&nbsp;<code>markForCheck</code>. To illustrate this advantage, consider the following example:</p> <pre> @Component({ selector: &#39;app-foo&#39;, standalone: true, changeDetection: ChangeDetectionStrategy.OnPush, template: `{{ num }}`, }) export class FooComponent { num = 1; private cdr = inject(ChangeDetectorRef); ngOnInit() { setTimeout(() =&gt; { this.num = 2; this.cdr.markForCheck(); }, 3000); } }</pre> <p>Here, we explicitly inject&nbsp;<code>ChangeDetectorRef</code>&nbsp;and invoke&nbsp;<code>markForCheck</code>&nbsp;after updating the component&#39;s state. The new way with signals:</p> <pre> @Component({ selector: &#39;app-foo&#39;, standalone: true, changeDetection: ChangeDetectionStrategy.OnPush, template: `{{ num() }}`, }) export class FooComponent { num = signal(0) ngOnInit() { setTimeout(() =&gt; this.num.set(1), 3000); } }</pre> <p>In this improved version, we use a&nbsp;<code>signal</code>, and remarkably, the view still updates without needing to manually call&nbsp;<code>markForCheck</code>. In this article, we will delve into the inner workings of this feature, shedding light on how signals streamline change detection in Angular applications.</p> <p>At a higher level of abstraction, you can conceptualize the current template as the&nbsp;<code>consumer</code>&nbsp;and every signal as the&nbsp;<code>producer</code>. When a signal undergoes a value change, it promptly notifies the template, which subsequently triggers a call to&nbsp;<code>markForCheck</code>.</p> <p><a href="https://netbasal.com/angulars-signal-revolution-effortless-change-detection-explained-unveiling-the-inner-workings-8a5e44c95b65">Click Here</a></p>