Signals and their inputs are great. I’m curious if there is a good way of using input changes beyond ngChanges(), rxjs-observables or even the new effect().

Is there a way to react to input-changes without those three?

Let’s assume we have a component “member” which has a input “id”. Whenever “id” changes, I want to reload data from a “MemberService”.

With ngChanges() I would do it like this:

@Input
id: number | undefined
ngOnChanges(changes: SimpleChanges) {
   if(changes.id) {
      this.memberSrv.load(this.id()).then((data: any) => this.data = data));
   }
}

With new signals like this:

id = input.required<number>();
constructor() {
   effect(async ()=>
      this.data = await this.memberSrv.load(this.id())
   );
}

The flaw on the signal-approach is that this.id() isn’t visible on first sight. It’s somewhere in the effect method.

We can also wrap signals within rxjs-Observables with “asObservable”, but then we rely on rxjs plus the signal is still wrapped/”hidden” in a function: asObservable(this.id)

Is there any way to subscribe to a input without using effect() or rxjs?

What is best practise to react on inputs?