issues encountered when transforming a class into an interface

My instructor recommended that I turn the class into an interface, as it is the correct way to do it.

export class Stats {  
  donePomodoros: number;
  doneShortBreaks: number;
  doneLongBreaks: number;

constructor() {
 this.donePomodoros = 0;
 this.doneShortBreaks = 0;
 this.doneLongBreaks = 0;
 }
}

However, when I converted it into an interface in the service, I encountered the following issue:

'Stats' only refers to a type, but is being used as a value here.

  private observableStats: BehaviorSubject<Stats> = new BehaviorSubject(
   new Stats()
  );

How can I resolve this problem?

Answer №1

Give it a shot:

export interface Data {
 completedTasks: number;
 completedErrands: number;
 completedProjects: number;
}

 private dataObservable: BehaviorSubject<Data> = new BehaviorSubject(
   {
     completedTasks: 5,
      completedErrands: 10,
      completedProjects: 3
    }
  );

In simple terms, you cannot directly instantiate interfaces. An interface defines the structure of an object by listing properties and methods without providing any implementation or initialization for them.

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