game-web-app.page.ts

@Component(...)
export class ProfilePage {
  ...
   
  async openGameApp() {
    try {
      const { token: userIdToken } = { token: '' } = await this.userService.getUserId();

      Browser.open(
        await lastValueFrom(
          this.gameService.buildGameUrl(userIdToken)
        )
      );
    } catch (err) {
      this.errorService.reportError(err);
    }
  }
}

game-web-service.ts

export class GameService {
   ...

  buildGameUrl(userIdToken: string) {
    return this.http.get(
      this.urlBuilder.build(GAME_FORMAT, {
        sessionId: this.sessionId,
      }, {
        queryParams: { userIdToken },
      })
    ).pipe(
      map(({ body: { formattedId } }): FormatUserIdResponse) => formattedId),
      filter((formattedId) => !!formattedId),
      map((formattedId) => `${ENV.GAME_WEB_APP_URL}?formattedId=${formattedId}`),
      throwIfEmpty(() => new Error('Failed to format token'),
    );
  }
}