在angular 6中如何从firebase实时数据库中获取基于键的单条记录

import { AngularFireModule } from '@angular/fire';
import { AngularFireDatabaseModule } from '@angular/fire/database';

// Firebase配置
const firebaseConfig = {
  apiKey: 'YOUR_API_KEY',
  authDomain: 'YOUR_AUTH_DOMAIN',
  databaseURL: 'YOUR_DATABASE_URL',
  projectId: 'YOUR_PROJECT_ID',
  storageBucket: 'YOUR_STORAGE_BUCKET',
  messagingSenderId: 'YOUR_MESSAGING_SENDER_ID'
};

@NgModule({
  imports: [
    AngularFireModule.initializeApp(firebaseConfig),
    AngularFireDatabaseModule
  ],
  // ...
})
export class AppModule { }

import { Component } from '@angular/core';
import { AngularFireDatabase } from '@angular/fire/database';

@Component({
  selector: 'app-your-component',
  template: `
    <div>{{ data | json }}</div>
  `
})
export class YourComponent {
  data: any;

  constructor(private db: AngularFireDatabase) { }

  ngOnInit() {
    const key = 'YOUR_RECORD_KEY';
    const ref = this.db.object('/your-collection/' + key).valueChanges();
    ref.subscribe(data => {
      this.data = data;
    });
  }
}