Is it possible to assign an interface as an argument of an arrow function?

Here is the code I have written:

interface ImyInterface {
    v: number;
}

class A implements OnInit {
   ngOnInit() {
       let myObservable$ = getObs();
       myObservable$.subscribe(data => {
           const foo = data as ImyInterface;
           foo. // <-- VS Code IDE autcompletes with 'v'
       });
   }
};

Despite this, I wanted to minimize extra variable declaration and attempted the following:

myObservable$.subscribe(data => {
     data = data as ImyInterface;
     data. // <-- VS Code IDE didn't autocomplete
});

Why did this alternative approach not work? Could it possibly be related to variable scope or shadowing? My understanding is limited since I am still a beginner.

Answer №1

Here is a recommended approach:

myObservable$.subscribe((data: ImyInterface) => {
    alert(data.v);
});

This code indicates that the subscribe function expects an argument that conforms to the ImyInterface interface.

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