Question

我的method返回了2018-01-22。但是，在我将其转换为2018-01-23以使用数组之前，此方法曾返回一个2018-01-22。

CollectionReference

在使用这种方式之前。努力工作以获取所有数据。

AngularFirestoreCollection<myObj>

现在，我使用了可选参数。

Observable<myObj[]>

如何将humanCol : AngularFirestoreCollection<Human>; humanObersArray: Observable<Human[]>; constructor(private db: AngularFirestore) { }转换为buildHuman(): Observable<Human[]> { this.humanCol = this.db.collection('path'); return this.humanObersArray = this.humanCol.valueChanges(); }或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 }); }？

Answer 1

您的函数buildHuman不返回任何内容。只需返回this.db.collection电话，您就会收到一个AngularFirestoreCollection。或像以前一样添加呼叫valueChanges以获得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();
}

在AngularFirestoreCollection <t>或Observable中转换CollectionReference？

1 个答案: