无法退订阿波罗角

Question

每当我导航到该页面时，订阅就增加了，我面临着取消订阅阿波罗的问题。 预期的行为：onDestroy应该取消所有订阅。 我自己的信念：我确实认为问题出在我从Apollo批量获取数据的方式上，我认为在加载的每个数据上都会创建一个新的订阅实例。因此，我需要取消订阅所有我无法成功执行的onDestroy实例。请任何帮助将不胜感激。

 `

  next = 150;
  offset = 0;
  invoiceHolder = [];


  getInvoices() { // Simulate old invoioce load
    this.invoicesSub = this.apollo.watchQuery<any>({
      query: invoices,
      variables: {
        offset: this.offset,
        first: this.next
      }
    }).valueChanges
      .subscribe(res => {
        const totalCount  = res.data.company.invoices.totalCount;
        this.offset = this.offset + this.next;
        this.invoiceAvailable.next({available: this.offset, totalCount});
        const result_array = [];
        this.invoiceHolder = result_array.concat(this.cleanData(res.data.company.invoices));
        this.invoices.next(this.invoiceHolder);
      });
  }



  ngOnDestroy() {
    (this.invoicesSub !== null) && this.invoicesSub.unsubscribe();
  }
    `