如何解决Angular-使用RxJS使用foreach多次调用http
这是我第一次在Angular项目中使用RxJS。我有足够的疑问,需要一些帮助。
这是我的原始代码
loadOperations() {
this.operationsListData = [];
this.operationsList = [];
this.operationsService.getoperations(this.selectedVariable).subscribe(data => {
this.operationsData = data;
if (data.length != 0) {
const variablesOperations = this.operationsData.map(p => p.variable_operations);
var arr = Object.getownPropertyNames(variablesOperations[0]);
arr.forEach(clave => {
var name = variablesOperations[0][clave];
this.operationsService.getoperationsByUuid(variablesOperations[0][clave],clave).subscribe(
data => {
data.name = variablesOperations[0][clave];
this.operationsListData.push(data);
},);
});
}
});
}
getoperationsByUuid(operation: string,uuid: string): Observable<OperationList> {
...
return this.http.get<OperationList>(url);
}
getoperations(selectedVariables: any): Observable<Operations[]> {
....
return this.http.get<Operations[]>(url);
}
现在我已经使用过RxJS。这就是我目前所拥有的。但是,它没有得到我所需要的。问题是concatMap。在我的原始代码中,我有一个遍历数组并调用服务的foreach。但是,我不知道如何在RxJS中编写该段代码或将其放入返回值中。
var variablesOperations;
const combined = this.operationsService.getoperationsByUuid(this.selectedVariable).pipe(
switchMap(data => {
this.operationsData = data;
if (data.length != 0) {
variablesOperations = data.map(p => p.variable_operations);
var arr = Object.getownPropertyNames(variablesOperations[0]);
console.log(arr);
return of(arr)
}
}),//This is wrong and it is what I need help with
concatMap((arrayClaves) => {
arrayClaves.forEach( clave => {
this.operationsListService.getoperationsByUuid(variablesOperations[0][clave],clave)
})
return null;
})
)
combined.subscribe(
data => {
console.log(data);
},err => {
console.log(err);
}
);
总而言之,我需要知道如何使用RxJS进行我的原始代码的foreach。谁能帮我吗?
解决方法
如果您只是想在管道内打电话或做某事,可以使用tap()。
例如:
myObservable.pipe(
tap(myValue => {
console.log(myValue);
}
);
,
尝试一下:
this.operationsService.getOperations(this.selectedVariable).pipe(
tap(data => this.operationsData = data),filter(data => data.length != 0),map(data => data.map(p => p.variable_operations)),switchMap(variablesOperations => {
return forkJoin(Object.getOwnPropertyNames(variablesOperations[0]).map(clave => {
return this.operationsService.getOperationsByUuid(variablesOperations[0][clave],clave).pipe(
map(data => ({ ... data,name: variablesOperations[0][clave] })),);
}));
}),).subscribe(operationsListData => this.operationsListData = operationsListData);
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