When to 'implement' interface in angular

Question

My question might be stupid, but i would like to get some clarity on this. As per my understanding, in angular we use interface to give idea about the data structure. So suppose we have an array of data of persons, we create an interface like

export interface Person {
  name: string;
  age: string
 }

And we can directly import this to our ts file and assign the type like

export class ComponentName implements OnInit {
data: Person[];
constructor() {}
ngOnInIt(){}
}

I totally understand this. But my confusion is, when do we 'implement' interface. I saw examples like

export class ComponentName implements OnInit, Person {
data: Person[];
constructor() {}
ngOnInIt(){}
}

Any help would be appreciatable. Thank you

In letter options, now your ComponentName MUST HAVE name and age fields ;) — Antoniossss
– Antoniossss, Commented Feb 10, 2022 at 12:23

Antoniossss · Accepted Answer · 2022-02-10 12:24:28Z

1

In letter options, now your ComponentName MUST HAVE name and age fields ;)

so construct like this class X implements Y says literally that X is an Y

Also keep in mind that in typescript declarations does not matter, but actual structure, so even without implements Person delcaration, if ComponentName would have name and age fields, person:Person=this would still be valid.

answered Feb 10, 2022 at 12:24

Antoniossss

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2 Comments

Pran R.V Over a year ago

So in first case, ie if we need to just assign the structure, we don't have to implement interface, we can directly import it and use?. Can you please explain further?

Antoniossss Over a year ago

data: Person[]; says that data is an array of Person. ComponentName implements Person Means that ComponentName class is a Person

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