angular - 验证数组中的对象也存在于可观察数组中

Question

我想验证以下数组中的对象:

const payment1: Payment = new Payment('1000'); // 1000 = id
const payment2: Payment = new Payment('1001');

const paymentArray: Payment[];
paymentArray.push(payment1, payment2);

存在于我的可观察数组中:

payments$: Observable<Payment[]>;

我想要的是得到一个不可观察的 bool 值作为结果。

我尝试过使用过滤器管道和 map 进行一些操作，但不幸的是无法让它工作:

this.paymentArray.forEach(element => {
  this.payments$.pipe(map(payments => payments.filter(payment => payment.id === element['id'])));
});

Answer 1

如果它是对象数组，则创建这些元素的映射以在过滤函数中进行比较。

ngOnInit() {

    this.idsToFind = ['1000', '1231', '2323'];
    const paymentArray: Payment[] = [];
    const payment1: Payment = new Payment('1000'); // 1000 = id
    const payment2: Payment = new Payment('1001');

    paymentArray.push(payment1, payment2);

    this.payments$ = of(paymentArray);

    const idsMap = this.idsToFind.reduce(
      (a, b) => { return { ...a, [b]: true } }, {}
    );
    console.log(idsMap);

    this.payments$
      .pipe(
        map((payments) =>
          payments.filter(
            (payment: Payment) => idsMap[payment.id])
        )
      )
      .subscribe((missings) => console.log(missings));

  }