加入扁平化数据

Question

我想将来自customers表的init数据加入到项目列表中.

模型是这样的:

• 项目

  • 键
  • name:string
  • 客户:customerKey

• 顾客

  • 键
  • name:string

你有一个例子,我如何使用angularfire2从angular2组件做到这一点？

我的控制器看起来像这样:

import { Component, OnInit } from '@angular/core';
import { Project } from '../project';
import { Router } from '@angular/router';
import { FirebaseAuth } from 'angularfire2';
import { AngularFire, FirebaseListObservable, FirebaseObjectObservable } from 'angularfire2';
import { Observable } from 'rxjs';

@Component({
  moduleId: module.id,
  selector: 'app-projects',
  templateUrl: 'projects.component.html',
  styleUrls: ['projects.component.css']
})
export class ProjectsComponent implements OnInit {

  projects: FirebaseListObservable<any[]>;
  customers: FirebaseListObservable<any[]>;
  projectName: string;
  constructor(
    private router: Router,
    private af: AngularFire
  ) { };

  ngOnInit() {
    this.projects = this.af.database.list('projects');
  }

  add(projectName: string) {
    this.af.database.list('projects')
      .push({ name: projectName, id: '123' });
    this.projectName = null;
  }
}

更新

我已经从FirebaseListObservable将this.projects的类型更改为Observable我的ngOnInit()方法现在看起来像这样:

ngOnInit() {
this.projects = this.af.database.list(`projects`)
  .map(projects => {
    projects.map(project => {
      this.af.database.object('customer/' + project.customer + '/name')
        .subscribe(customer => {
          project.customer = customer;
        })
      return project;
    })
    return projects;
  });
}

我现在可以从里面的模板访问不是客户的名称属性

<li *ngFor="let project of projects | async">

project.customer.$value

Answer 1

不太确定您的数据集是什么样子，所以我只写一个基本示例。假设结构如下：

- projects
  - key
    - name: string
    - customers
      - customerKey: boolean

- customers
  - key
    - name: string

示例数据

- projects
  - projectId1
    - name: "Cool project!",
    - customers
      - customerId1: true,
      - customerId2: true
  - projectId2
    - name: "Another cool project!",
    - customers
      - customerId2: true,
      - customerId3: true

- customers
  - customerId1
    - name: "John Smith"
  - customerId2
    - name: "John Doe"
  - customerId3
    - name: "John John"

因此，我们将客户的密钥存储在每个项目的customers属性中。

假设我们想要列出每个项目，但我们还想获取客户的真实姓名，而不仅仅是他们的 ID。由于 firebase 没有连接，我们必须手动执行此操作。这是一种方法：

this.projects = this.af.database.list(`projects`)
  .map(projects => {
    return projects.map(project => {
      project.customers.map(customer => {
        this.af.database.list(`customers`)
          .subscribe(c => {
            customer = c;
          });
      });
      return project;
    });
  });

如果您想异步获取数据，可以将内部.subscribe更改为简单的（在本例中使用模板中的管道）。.mapasync