从AngularFireList获取物品的问题

Question

当我尝试通过AngularFireList中的属性之一寻找对象时，我无法获得该对象。你有什么建议？

Firebase Table Structure

服务

import { Injectable } from '@angular/core';

import { AngularFireDatabase, AngularFireList } from 'angularfire2/database';

import { Prestamo } from '../models/prestamo';
import { FirebaseDatabase } from 'angularfire2';

@Injectable({
  providedIn: 'root'
})
export class PrestamoService {

  prestamoLista: AngularFireList<any>;
  prestamoSeleccionado: Prestamo = new Prestamo();

  constructor(private firebase: AngularFireDatabase) {}



  obtenerPrestamo(codigo: string)
  {
    return this.prestamoLista = this.firebase.list('prestamos', ref => ref.orderByChild('codigo').equalTo(codigo));
  }
}

Answer 1

您可能正在使用valueChanges来解决此问题：

.snapshotChanges()
  .pipe(map(items => {
    return items.map(a => {
      const data = a.payload.val();
      const key = a.payload.key;
      return {key, ..data};   
    });

然后您可以订阅此内容。