I promised I'll switch to new Observable - for our rxjs blog post

expose-obs.ts

  private async getTheBand(name: string): Promise<Artist> {
    const artist = await import('../../../wasm/pkg/rust_wasm_part');
    return artist.query_band(name);
  }

  getTheBand$(name): Observable<Artist> {
    return defer(() => this.getTheBand(name));
  }