Firebase Firestore 显示警告

Question

我正在做一个项目，使用 ionic 3 和 firebase firestore 作为数据库。

但是每当我进行 CRUD 操作时，我的 firebase firestore 都会显示警告。

 index.esm.js:77 [2018-05-02T05:45:40.408Z]  @firebase/firestore: 
 Firestore (4.13.0): 
 The behavior for Date objects stored in Firestore is going to change
 AND YOUR APP MAY BREAK.
 To hide this warning and ensure your app does not break, you need to 
 add the
 following code to your app before calling any other Cloud Firestore 
 methods:

 const firestore = firebase.firestore();
 const settings = {/* your settings... */ timestampsInSnapshots: 
 true};
 firestore.settings(settings);

 With this change, timestamps stored in Cloud Firestore will be read 
 back as
 Firebase Timestamp objects instead of as system Date objects. So you 
 will also
 need to update code expecting a Date to instead expect a Timestamp. 
 For example:

 // Old:
 const date = snapshot.get('created_at');
 // New:
 const timestamp = snapshot.get('created_at');
 const date = timestamp.toDate();

 Please audit all existing usages of Date when you enable the new 
 behavior. In a
 future release, the behavior will change to the new behavior, so if 
 you do not
 follow these steps, YOUR APP MAY BREAK.

Answer 1

我在 app.module.ts 中添加了以下代码，然后错误更正。

firebase.initializeApp(environment.firebase) // 加载 firebase 服务器设置

firebase.firestore().settings( { timestampsInSnapshots: true })

Answer 2

我刚刚重新安装了“angularfire2”。 问题已经解决了。

• npm 卸载 angularfire2
• npm install angularfire2@5.0.0-rc.9

发布版本信息：https://github.com/angular/angularfire2/releases

Answer 3

我遇到了同样的问题，如果您使用 Angular 和 angularfire2 这可能会对您有所帮助：

如警告所示，您应该在应用初始化时将 timestampsInSnapshots 属性设置为 true。你可以在AppComponent的构造函数中调用它：

import { AngularFirestore } from 'angularfire2/firestore';

export class AppComponent {

    constructor(db: AngularFirestore) {
        const settings = { timestampsInSnapshots: true };
        db.app.firestore().settings(settings);   
    }

}

为避免警告，您可以设置设置类型：

import { AngularFirestore } from 'angularfire2/firestore';
import * as firebase from 'firebase';

export class AppComponent {

    constructor(db: AngularFirestore) {
        const settings: firebase.firestore.Settings = { timestampsInSnapshots: true };
        db.app.firestore().settings(settings);   
    }

}

AppModule的构造函数也是调用这段代码的好地方，用什么看你自己。

Answer 4

实施此设置后，日期将不再以 javascript Dates 的形式返回。它们将是 Firestore 时间戳。您的代码很可能会受到影响。我创建了以下函数来将任何对象的任何 Timestamp 属性转换为 javascript Date 属性。

private convertFirestoreTimestampsToDates(myObject: any): void {
  for (let propertyName in myObject) {
    if (myObject.hasOwnProperty(propertyName)) {
      if (myObject[propertyName]) {
        if (myObject[propertyName].__proto__.constructor.name === 'Timestamp') myObject[propertyName] = myObject[propertyName].toDate();
      }
    }
  }
}

Answer 5

为了增强来自“farkasnorbert90”的答案，我在 app.component.ts 中使用了 afs.firestore.settings 而不是 db.app.firestore()

import * as firebase from 'firebase';
import { AngularFirestore } from 'angularfire2/firestore';

  constructor(
    public auth: AuthService,
    afs: AngularFirestore,
  ) {
    const settings: firebase.firestore.Settings = {
      timestampsInSnapshots: true,
    };
    afs.firestore.settings(settings);
  }