使用angularfire2，如何编写作为字段子级生成的新密钥

Question

I'm trying to write the new key generated on push inside an child field.

Is it possible to write on the same write transaction? something like below...

const evt = this.angularfire2Service.afDb.list('/path/');
evt.push({
    id : <<<< key generated on push >>>>>
    title: newdata.title,
 }).then( newrec => {
        console.log('chave = ', newrec.key)
});

as workaround, I can write as:

.then( newrec => {
     console.log('chave = ', e.key);
     this.angularfire2Service.afDb.object('/path/+newrec.key).update({
        id: newrec.key
     });
});

Answer 1

I would suggest using firebase sdk for that. Indeed, key is already generated when using .push() ie

import * as firebase from 'firebase';

Then

const ref = firebase.database().ref('/path').push();

ref.set({
    id: ref.key,
    title: newdata.title
});

Answer 2

With angularfire2, on your event.service.ts , you need to...

import { AngularFireDatabase } from 'angularfire2/database';

@Injectable()
export class EventService {
  userKey: string;

  constructor(private _fbApp: AngularFireDatabase) {}

  addEvent(event) {
    // creating key without pushing data
    this.eventKey = this._fbApp.database.ref('/events').push().key;
    // adding the key as a property to the object you will push
    event.uid = this.eventKey;
    // creating child node with same key and pushing data
    this._fbApp.database().ref('/events').child(this.eventKey).set(event);
}

In your event.component.ts ...

addEvent({ value, valid }: { value: Event; valid: boolean }) {
  this._eventService.addEvent(value);
  this._router.navigate(['/']);
}

Notice the {value: Event; in case you have an interface to validate your object.

This code should create a node key right before you are pushing the data, storing that key in a variable, and right away including the key as a property in the object you are pushing to the node. Notice the .child(this.eventKey) is using the just created key as the key node.

Hope this helps!!!