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Angular11 rxjs switchmap即使在外部可观测触发时也不工作

angular11 rxjs

Mukil Deepthi · 技术社区 · 3 年前

我正在尝试以下基本上需要触发每次过滤器得到改变。Cananyone请帮助我,使用高阶观测值有什么不对。

工作版本:

this.filterservice.registerFilters({
                key: this.FILTERS_KEY,
                filters: this.AUDIT_FILTERS,
                sorts: [new DateSort({ for: 'modifiedOn' })]
            }).pipe(
                takeUntil(this.destroy$)
            ).subscribe(filters => {
                this.filters = filters;
                this.auditBuilderListService.changeFilter(filters);
                this.auditData$ = this.auditBuilderListService.auditBuilderData$;
            });

使用switchmap(不工作):

registerFilters$ = this.filterservice.registerFilters({
        key: this.FILTERS_KEY,
        filters: this.AUDIT_FILTERS,
        sorts: [new DateSort({ for: 'modifiedOn' })]
    });

    auditData$ = this.registerFilters$.pipe(
        switchMap((filters) => {
            this.filters = filters;
            this.auditBuilderListService.changeFilter(filters);
            return this.auditBuilderListService.auditBuilderData$;
        }),
        takeUntil(this.destroy$)
    );

在职:

auditBuilderData$ = combineLatest([
    this.pageNumberSubject,
    this.filterAction$
]).pipe(
    switchMap(([currentPage, filterParameters]) => {
        return this.getAudits(filterParameters, currentPage, this.pageSize);
    }),
    shareReplay(1)
);

不带开关映射的工作版本: auditData$:可观察的;

registerFilters$ = this.filterservice.registerFilters({
    key: this.FILTERS_KEY,
    filters: this.AUDIT_FILTERS,
    sorts: [new DateSort({ for: 'modifiedOn' })]
}).pipe(
    tap(filters => {
        this.auditBuilderListService.setPage(1);
        this.filters = filters;
        this.auditBuilderListService.changeFilter(filters);         
    }),
    takeUntil(this.destroy$)
);

    this.registerFilters$
        .pipe(takeUntil(this.destroy$))
        .subscribe(filters => {
            this.auditData$ = this.auditBuilderListService.auditBuilderData$;
        });

但有没有更好的方法来实现同样的目标?

0 回复 | 直到 3 年前

Joshua McCarthy 3 年前

关于 auditBuilderListSerivce ,我假设 changeFilter() 结果 auditBuilderData$ 释放一个新的值。如果是这种情况,它解释了为什么你的开关地图不起作用。你回来了 auditBuilderData$ 太晚了,因为它在你调用的那一刻就释放出了它的价值 changeFilter() .

至于解决方案,你可以选择 changeFilter() 返回要发出的值(如果可能)。另一个选择是引用和订阅 auditBuilderData$ 分别地

registerFilters$ = this.filterservice.registerFilters({
  key: this.FILTERS_KEY,
  filters: this.AUDIT_FILTERS,
  sorts: [new DateSort({ for: 'modifiedOn' })],
}).pipe(
  tap(filters =>{
    this.filters = filters;
    this.auditBuilderListService.changeFilter(filters);
  }),
  takeUntil(this.destroy$)
);

auditData$ = this.auditBuilderListService.auditBuilderData$;
  takeUntil(this.destroy$)
);

当你对这两个观测都有一个活跃的订阅, registerFilters$ 将调用 changeFilter() 作为副作用 auditData$ 释放它的新价值。