[英]RxJs: Combine two Observables - Take all from first but not all from second
[英]RxJs: Executing 3 observables one after another and using results from first in second, and first and second in third requests
我需要能夠一個接一個地執行3個可觀察變量,以便可以在第二個中使用第一個結果,在第三個中使用第一個和第二個結果。
這樣的事情( 由於serviceId在第三個請求中不可見,因此不起作用 ):
private setupStuff(): void {
this.initRouteParams().pipe(
switchMap(serviceId => this.getFileInfo(serviceId)),
switchMap(fileName => this.getExistingFile(serviceId, fileName)
.subscribe(response => {
console.log(response);
}))
);
}
您可以將serviceN的值顯式返回給serviceN + 1。 這是個主意:
private setupStuff() {
this.initRouteParams()
.pipe(
switchMap(serviceId => {
return zip(of(serviceId), this.getFileInfo(serviceId))
}),
switchMap(([serviceId, filename]) => {
return zip(of(serviceId), of(filename), this.getExistingFile(serviceId, filename))
})
)
.subscribe(([serviceId, filename, response]) => {
console.log(serviceId, filename, response);
})
}
編輯:
您可以通過顯式聲明每個輸入的類型來修復類型錯誤。 您可能想為response
分配適當的類型。
設法這樣解決:
private checkFilePresence(): void {
const first$: Observable<string> = this.initRouteParams();
const second$: Observable<string> = first$.pipe(
switchMap(config => {
return this.getFileInfo(config);
})
);
const third$: Observable<CkitExistingFileResponse> = combineLatest(first$, second$).pipe(
switchMap(([config, second]) => {
return this.getExistingFile(config, second);
})
);
combineLatest(first$, third$)
.subscribe(() => {
});
}
您可以按以下順序訂閱可觀察對象:
private setupStuff(): void {
this.initRouteParams().subscribe( serviceId => {
this.getFileInfo(serviceId).subscribe(fileName => {
this.getExistingFile(serviceId, fileName).subscribe( response => {
console.log(response);
});
});
});
}
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