角度订阅链可观察

Question

我有一项服务，可以链接一组HTTP请求并返回产品列表。 这是我到目前为止的内容：

var books = {
  "mainKey1": {
    "History" : [
      {"hai" : "hello"},
      {"hai" : "bye"}
    ],
    "tempKey" : "tempValue"
  },
  "mainKey2":{
    "Number": "AD-3424",
    "Number1": "AD-3424"
  },
  "temparr" : [
    "ai",
    "bi"
  ]

};

function replaceKeys(books,replacementkeys,newKeyJson) {
  if(typeof books == 'object') {    
    newKeyJson = Object.keys(books).map((book) => {
      if(typeof books[book] == 'object' || Array.isArray(books[book]) ) {
        replaceKeys(books[book],replacementkeys,newKeyJson[book])
      }
      if(replacementKeys[book]) {
          newKeyJson[replacementKeys[book]] = books[book];          
          delete newKeyJson[book];          
      }
    })

  }
  else if(Array.isArray(books)) {
   for( var i=0;i< books.length;i++) {
        replaceKeys(books[i],replacementkeys,newKeyJson[i]);
   }
  }else if(typeof books == 'string') {
    return;
  }else {
    return;
  }
}

var replacementKeys = {"History" : "replaced History","hai" : "hi","Number" : "test","Number1" : "test2","mainKey1" :"sidekey","tempKey" : "realKey","mainKey2" :"side2"};
var newKeyJson = Object.assign({},books);
replaceKeys(books,replacementKeys,newKeyJson);
console.log(newKeyJson); //this will contain object with updated keys

在我的控制器中，我称之为：

listForDisplay(categoryId: string): Observable<any[]> {
    if (!categoryId) return of([]);
    return this.listFields(categoryId);
}

private listFields(categoryId: string): Observable<any[]> {
    return this.fieldService.list(categoryId, true).pipe(
        flatMap((fields: Field[]) => {
            if (!fields) return of([]);
            return this.listProducts(categoryId, fields);
        }),
    );
}

private listProducts(categoryId: string, fields: Field[]): Observable<any[]> {
    return this.productService.listSpecificationProducts(categoryId).pipe(
        flatMap((products: any[]) => {
            if (!products) return of([]);
            return this.mapVisibleFields(fields, products);
        }),
    );
}

private mapVisibleFields(fields: Field[], products: any[]): any[] {
    console.log(products);
    return this.productModelService.mapProductsWithSpecificationFields(fields, products);
}

问题在于第一部分的private getCategory() { this.selectorSubscription = this.selectorService.category.subscribe(categoryId => { this.products = []; this.specificationService.listForDisplay(categoryId).subscribe((products: any[]) => { console.log(products); this.products = products; }); }); } 返回一个数组。 控制器中的console.log仅返回一个项目。...

赞：

我显然做错了什么。 有人可以帮忙吗？

Answer 1

根据rxjs documentation，flatMap

  

将每个源值投影到一个Observable中，该值将合并到   输出可观察。

这就是为什么您的订阅被多次调用，每个值一次出现的原因。您确定需要flatMap吗？从您想做的事情看来，map会更合适。