如何组合2个combineLatest来绕过6个参数的限制

Question

combineLatest可以作为输入的参数的最大数量是 6。

更具体地说，它采用一个最多可包含 6 个元素的数组作为输入。这样可以自动推断类型。

因此，如果在下面的代码中添加我会this.someMethodReturningObservable7()破坏它：

someMethod(...) {
  return combineLatest([
    this.someMethodReturningObservable1(),
    this.someMethodReturningObservable2(),
    this.someMethodReturningObservable3(),
    this.someMethodReturningObservable4(),
    this.someMethodReturningObservable5(),
    this.someMethodReturningObservable6(),
    this.someMethodReturningObservable7(), // this causes problems
  ]).pipe(
    map(([arg1, arg2, arg3, arg4, arg5, arg6, arg7]) => ({
      arg1,
      arg2,
      arg3,
      arg4,
      arg5,
      arg6,
      arg7,
    })),
    // do more stuff
  );
}

只要我将其保持在 6 个参数，它就可以正常工作。超过6个就不行了。

我怎样才能将其分解为几个，combineLatest每个最多有 6 个参数？

Answer 1

您可以将两个 mergeLatests 合并为一个，如下所示：

import { of, combineLatest, interval } from "rxjs";
import { map, take } from "rxjs/operators";

const num0$ = of(0 as const);
const num1$ = of(1 as const);
const num2$ = of(2 as const);
const num3$ = of(3 as const);
const num4$ = of(4 as const);
const num5$ = of(5 as const);
const num6$ = of(6 as const);
const num7$ = of(7 as const);
const num8$ = of(8 as const);
const num9$ = interval(1000).pipe(take(3), map(() => 9 as const));

const numsPartOne$ = combineLatest(num0$, num1$, num2$, num3$, num4$);
const numsPartTwo$ = combineLatest(num5$, num6$, num7$, num8$, num9$);

const numCombined$ = combineLatest([numsPartOne$, numsPartTwo$]).pipe(
  // use [[..] [..]] to spread both arrays
  map(([[num0, num1, num2, num3, num4], [num5, num6, num7, num8, num9]]) => {
    // num0 has type 0, etc.
    return {
      num0,
      num1,
      num2,
      num3,
      num4,
      num5,
      num6,
      num7,
      num8,
      num9
    };
  })
);
numCombined$.subscribe(mappedNums => console.log(mappedNums));