更新 .snapshotChanges() 代码以使用 angularfire2 5.0..0 rc-8、firebase 5.0.2

Question

我已成功更新 angularfire 5.0.0.rc 8 和 firebase 5.0.2，没有错误模块。我想我要做的最后一件事是更改此代码以检索所有数据

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';
import { IonicPage } from 'ionic-angular/navigation/ionic-page';
import { Observable } from 'rxjs';
import 'rxjs/add/operator/map';
import { Note } from '../../model/note/note.model';
import { NoteListService } from '../../services/note-list.service';

@IonicPage()
@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  noteList: Observable<Note[]>

  constructor(public navCtrl: NavController, private noteListService: NoteListService) {
    this.noteList = this.noteListService.getNoteList()
      .snapshotChanges()
      .map(
        changes => {
          return changes.map(c => ({
            key: c.payload.key, ...c.payload.val()
          }))
        });
  }
}

noteListService 的文件...

import { Injectable } from '@angular/core';
import { AngularFireDatabase } from 'angularfire2/database';
import { Note } from '../model/note/note.model';

@Injectable()
export class NoteListService {

    private noteListRef = this.db.list<Note>('note-list');

    constructor(private db: AngularFireDatabase) { }

    getNoteList() {
        return this.noteListRef;
    }

    addNote(note: Note) {
        return this.noteListRef.push(note);
    }

    updateNote(note: Note) {
        return this.noteListRef.update(note.key, note);
    }

    removeNote(note: Note) {
        return this.noteListRef.remove(note.key);
    }
}

帮助更改此代码，使其与我的新版本 angularfire 5.0.0 rc 8 和 firebase 5.0.2 兼容

这是我的一半代码工作后的新错误.. 插入部分。但我仍然无法查询

Runtime Error
Uncaught (in promise): TypeError: this.noteListService.getNoteList(...).snapshotChanges(...).map is not

函数 TypeError: this.noteListService.getNoteList(...).snapshotChanges(...).map 不是新主页 ( http://localhost:8100/build/0.js:86:14 ) 上的函数createClass ( http://localhost:8100/build/vendor.js:10575:20 ) 在 createDirectiveInstance ( http://localhost:8100/build/vendor.js:10458:20 ) 在 createViewNodes ( http://localhost: 8100/build/vendor.js:11680:36 ) 在 createRootView ( http://localhost:8100/build/vendor.js:11594:5 ) 在 callWithDebugContext ( http://localhost:8100/build/vendor.js: 12629:25 ) 在 Object.debugCreateRootView [as createRootView] ( http://localhost:8100/build/vendor.js:12116:12 ) 在 ComponentFactory_.create (http://localhost:8100/build/vendor.js:9938:29 ) 在 ComponentFactoryBoundToModule.create ( http://localhost:8100/build/vendor.js:3914:29 ) 在 NavControllerBase._viewInit ( http:// localhost:8100/build/vendor.js:49286:44 ) 堆栈错误：未捕获（承诺）：类型错误：this.noteListService.getNoteList(...).snapshotChanges(...).map 不是函数

Answer 1

您没有正确地从 rxjs 导入 map 操作符，同样从 rxjs 6 开始，您需要使用pipe.

...
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

@IonicPage()
@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  noteList: Observable<Note[]>

  constructor(public navCtrl: NavController, private noteListService: NoteListService) {
    this.noteList = this.noteListService.getNoteList()
      .snapshotChanges()
      .pipe(
        map(changes => 
          changes.map(c => ({
            key: c.payload.key, ...c.payload.val()
          }))
        })
      );
  }
}