Is there a way to retrieve a particular object from a versatile function?

Here is a generic function to consider:

  public getData<T>(url: string): Observable<T> {
    return this.httpClient.get<T>(url);
  }

I am looking for a way to test this function by returning a mock object array, especially if the remote API is not available yet.

This is what I want to return:

return of([{id: 1, value: 'test1'}, {id: 2, value: 'test2'}]);

However, when I try to do this, I encounter an error:

TS2322: Type 'Observable<{ id: number; value: string; }[]>' is not assignable to type 'Observable'.   Type '{ id: number; value: string; }[]' is not assignable to type 'T'.     'T' could be instantiated with an arbitrary type which could be unrelated to '{ id: number; value: string; }[]'.

Is there a way to resolve this issue?

Answer №1

bringing back([{id: 1, value: 'test1'}, {id: 2, value: 'test2'}] as mysterious T); 

This does the magic. Additionally, as any as T is supposed to function based on my understanding.

Answer №2

For a TS experiment, give this a shot: 

type CustomType = {
      numberID: number;
      textValue: string;
    };


fetchData(): Observable<CustomType[]> {
    return of([
      { numberID: 1, textValue: "example1" },
      { numberID: 2, textValue: "example2" },
    ]);
  }

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