I have an interface called IUser and uses strictNullChecks in the typescript setting. I want to use a variable of IUser in the class like below:
class UserAccount {
user: IUser;
}
The above code will generate the error:
Property 'user' has no initializer and is not definitely assigned in the constructor.
I can fix this with:
class UserAccount {
user: IUser;
constructor() {
user = new User();
}
}
But from a run time perspective, the user can be set only after a while after the display is complete. There is a latency for getting the data for the user from the server. The setting of the user is done through an RxJS observable which works only reactively.
What type of initialization I can do for user so that it can be set only later time. Setting user to null or undefined may not be correct because I use strictNullChecks and showing the intention that the object will be present from the beginning. But a valid object for user can't exist until the server call is complete.
*** UPDATE ****
This is a little more better example than the above:
export class AddPersonDialogComponent {
selectedPerson1: IPersonForTypeahead;
selectedPerson2: IPersonForTypeahead;
selectedPerson3: IPersonForTypeahead;
...
}
The 3 selectedPerson objects are assigned values when the user select them from three 3 dropdowns in the dialog. These three properties start with nothing but if the user select people from a drop down in the dialog, they are set.
You could make your usage of UserAccount to be an observable, like this:
userAccount$: Observable<UserAccount> = this.service.getUser().pipe(
map(user => new UserAccount(user))
);
The idea here is to not construct your UserAccount until you have all the data needed to do so. This goes along with your idea "But a valid object for user can't exist until the server call is complete" .