问题描述
我的方法正在返回CollectionReference
.但是,在将AngularFirestoreCollection<myObj>
转换为Observable<myObj[]>
以使用数组之前,此方法用于返回AngularFirestoreCollection<myObj>
.
My method is returning a CollectionReference
.However, this method used to return a AngularFirestoreCollection<myObj>
before I converted it to Observable<myObj[]>
to work with arrays.
humanCol : AngularFirestoreCollection<Human>;
humanObersArray: Observable<Human[]>;
constructor(private db: AngularFirestore) { }
在我使用这种方式之前.出色的工作可以获取所有数据.
buildHuman(): Observable<Human[]> {
this.humanCol = this.db.collection('path');
return this.humanObersArray = this.humanCol.valueChanges();
}
现在,我使用了可选参数.
buildHuman(param1: string, param2?: string, param3?: string...){
this.db.collection('path', ref => {
let retVal = ref as any;
if (param1 != null) { retVal = retVal.where('param1', '==', param1) }
if (param2 != null) { retVal = retVal.where('param2', '==', param2) }
if (param3 != null) { retVal = retVal.where('param3', '==', param3) }
...
return retVal; //this return a CollectionReference
});
}
如何将retVal
转换为AngularFirestoreCollection<T>
或Observable
?
推荐答案
您的函数buildHuman
不返回任何内容.只需返回this.db.collection
调用,您就会得到一个AngularFirestoreCollection
.或像以前一样添加呼叫valueChanges
以获得observable
:
Your function buildHuman
doesn't return anything. Just return the this.db.collection
call and you get a AngularFirestoreCollection
. Or add call valueChanges
like before to get an observable
:
buildHuman(param1: string, param2?: string, param3?: string): AngularFirestoreCollection<any> {
return this.afs.collection('users', ref => {
let retVal = ref as any;
if (param1 != null) { retVal = retVal.where('param1', '==', param1); }
if (param2 != null) { retVal = retVal.where('param2', '==', param2); }
if (param3 != null) { retVal = retVal.where('param3', '==', param2); }
return retVal;
});
}
OR
buildHuman(param1: string, param2?: string, param3?: string): Observable<any> {
return this.afs.collection('users', ref => {
let retVal = ref as any;
if (param1 != null) { retVal = retVal.where('param1', '==', param1); }
if (param2 != null) { retVal = retVal.where('param2', '==', param2); }
if (param3 != null) { retVal = retVal.where('param3', '==', param2); }
return retVal;
})
.valueChanges();
}
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