Angularfire: Please support transaction API

[mhevery]

https://www.firebase.com/docs/web/api/firebase/transaction.html

My guess is that it should be on FirebaseObjectObservable.transaction

[jeffbcross]

Yes, also FirebaseListObservable should have this.

[mhevery]

@jeffbcross Why do you think that @vicb should do this?

[jeffbcross]

I thought @vicb said he was going to work on it once the upgrade to
firebase sdk v3 was done, but maybe I misunderstood.
On Fri, Jun 3, 2016 at 1:44 PM Miško Hevery [email protected]
wrote:

@jeffbcross https://github.com/jeffbcross Why do you think that @vicb
https://github.com/vicb should do this?

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[vicb]

Yep Jeff, that's what we agrreed on

[davideast]

@vicb Are you still up to the task? If not I can handle it 👍

[vicb]

I was about to do it but because you insist, please take over ;)

It would be nice that you update periscope once angularfire supports it. Ping me if you need more info.

Thanks !!

[katowulf]

I'm having trouble coming up with benefits of adding transactions into AngularFire2. All the reasons I might use transactions are already covered by the SDK and I don't see any pain points we can solve here. It feels like a straight wrapper on the methods. Can you guys push out some use cases on why one wouldn't go straight to the SDK for this?

[vicb]

@katowulf you're right - that actually what we ended up doing - forgot to close the issue, sorry

edit: can not close this myself

[elekzalan]

Can you mention this somewhere in the documentation, please? I'd say it would be useful to have a part in the docs where you clarify your policy about this.

[ross-nordstrom]

:+1: on mentioning how to do this in the docs

[idoghoo]

Hi, just wondering if an explanation on how to perform transactions ended up in the docs? Thanks

[dprof-johan]

Hi,

I'm trying to figure this one out too. Is there any documentation / examples?

[katowulf]

Docs on transactions are here: https://firebase.google.com/docs/database/web/save-data#save_data_as_transactions

[larssn]

Isn't the argument for adding transaction support to Angularfire that in order to support tree shaking properly, we should refrain from using the firebase import?

[davideast]

@larssn You should avoid importing all of firebase. There is no harm in importing the app/typings if you have already included the AngularFireModule and/or AngularFireDatabaseModule.

// imports only typings and app which should already be imported
import * as firebase from 'firebase/app';

You can also access the App or Database instance off of the AngularFireDatabase service.

constructor(afDb: AngularFireDatabase) {
  const firebaseDb = afDb.database;
  const firebaseApp = adDb.app;
}

[larssn]

@davideast Appreciate the fast response! I'll play around with your suggestions.

[larssn]

@davideast Seems its located on afDb.app.database. (This is on 4.0 Rc0)

[markgoho]

@larssn I just had to use .transaction() in my project, so I thought I'd share my code in case you're still working it out.

import { FirebaseApp } from 'angularfire2';
...
constructor(
    private fbApp: FirebaseApp,
) {}

pushStoryToCategories(categories: string[]) {
  categories.forEach(category => {
    const catRef = this.fbApp.database().ref(`/categories/${category}/count`);
    catRef.transaction(count => count + 1);
  }
}

I've stripped out non-essential code, but beyond the imports and injection, it's two lines of code.

[GiselleSerate]

This thread got me most of the way there, but after the recent update, I had to do it this way:

import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule, AngularFireDatabase } from 'angularfire2/database';

export class User {
  db: AngularFireDatabase;

  constructor(db: AngularFireDatabase) {
    this.db = db;
  }

  addDebt(amount: number) { 
    this.db.object('/users/'.concat(this.currentUserID,'/debts/',this.userID)).$ref.ref.transaction(debt => debt + amount);
  }
}

Hope this helps!

(Edit: Simplified code paste.)

[RicardoVM64]

thank you so much for your response😄
when it was the las update?

[markgoho]

For Firestore Transactions, the process is similar:

import { FirebaseApp } from 'angularfire2';
...
export class QuestionComponent implements OnInit {
  questionRef;

  constructor(private fb: FirebaseApp) {}
  ngOnInit() {
    this.questionRef = this.fb.firestore().collection('questions').doc(this.id);
  }

  voteYes() {
    this.fb.firestore().runTransaction(transaction => {
      return transaction.get(this.questionRef).then(question => {
        const newVotes = question.data().yesVotes + 1;
        transaction.update(this.questionRef, { yesVotes: newVotes });
      });
    });
  }

[aaronfrost]

@markgoho I was just wondering about this, and you commented less than an hour ago. Very cool fo you and coincidental.

[davideast]

@markgoho @aaronfrost Would you two be interested in an observable form of this API?

[aaronfrost]

vs Promise based... why not. Not a huge pain to deal with a promise here.

[markgoho]

@davideast I would love to see something observable based!

[aaronfrost]

I should PR this to the documentation. It's sad that it's buried all the way over here in this 18 month old closed issue.

[cengiz-dev]

Can anyone take a look at https://stackoverflow.com/questions/50215622/firebase-database-transaction-with-angularfire2 ? I can't get this to work.