Question 118909 in Firebase Question posted in
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Firebase-admin with Typescript rejects all FieldValues

I am using firebase-admin to control a firestore database using Cloud Functions with TypeScript. If I set the type of my collection reference, I can no longer add using FieldValues. The argument types from add require a literal object matching the collection document, without any FieldValues. What is a supported pattern for using FieldValues with firebase-admin in TypeScript? Any answer using the base libraries with FieldValues will do.

Here is a minimal example with FieldValue.serverTimestamp:

import { firestore, initializeApp } from 'firebase-admin'
import { firebaseConfig } from './secret'
import { https } from 'firebase-functions'

interface User {
  id?: string
  displayName: string
  createdAt: firestore.Timestamp
}
const converter = {
  toFirestore: (data: User) => data,
  fromFirestore: (snapshot: firestore.QueryDocumentSnapshot<User>): User => {
    const data = snapshot.data()
    const doc = { id: snapshot.id, ...data }
    return doc
  }
}
initializeApp(firebaseConfig)
const db = firestore()
const usersCollectionRef = db.collection('users').withConverter(converter)
export const cloudFunction = https.onCall(async (props, context) => {
  const newUserData = {
    displayName: 'New User',
    createdAt: firestore.FieldValue.serverTimestamp()
  }
  await usersCollectionRef.add(newUserData)
  // Argument of type '{ displayName: string; createdAt: firestore.FieldValue; }' is not assignable to parameter of type 'User'.
  // Types of property 'createdAt' are incompatible.
  // Type 'FieldValue' is missing the following properties from type 'Timestamp': seconds, nanoseconds, toDate, toMillis
})

Similarly, with FieldValue.arrayUnion:

interface User {
  id?: string
  friendNames: string[]
}
const converter = {
  toFirestore: (data: User) => data,
  fromFirestore: (snapshot: firestore.QueryDocumentSnapshot<User>): User => {
    const data = snapshot.data()
    const doc = { id: snapshot.id, ...data }
    return doc
  }
}
initializeApp(firebaseConfig)
const db = firestore()
const usersCollectionRef = db.collection('users').withConverter(converter)
export const cloudFunction = https.onCall(async (props, context) => {
  await usersCollectionRef.add({
    friendNames: firestore.FieldValue.arrayUnion('BFF')
    // Type 'FieldValue' is missing the following properties from type 'string[]': length, pop, push, concat, and 29 more.

  })
})
Tags:

2

Answers


  1. 0

    I think you need to define createdAt as Timestamp Type

    import type { Timestamp } from 'firebase-admin/firestore';

interface User {
  displayName: string
  createdAt: Timestamp
}

    I believe this should fix the problem

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  2. 0

    Try this

    import * as admin from 'firebase-admin'
import { Timestamp } from 'firebase-admin/firestore'

interface UserType {
  id?: string
  displayName: string
  createdAt: Timestamp
  // update
  friends: string[]
}

....

// creates a firestore hanlder
export const firestore = Object.assign(
  () => {
    return admin.firestore()
  }, {
    doc: <T>( path: string ) => {
      return admin.firestore()
        .doc( path )
        .withConverter<T>( converter<T>() )
    },
    collection: <T>( path: string ) => {
      return admin.firestore()
        .collection( path )
        .withConverter<T>( converter<T>() )
    },
    // update
    fieldValue: admin.firestore.FieldValue
  } )
// typed converter
const converter = <T>() => ( {
  toFirestore: ( data: any ) => data,
  fromFirestore: ( doc: any ) => {
    return {
       ...doc.data(),
       id: doc.id
    } as T
  }
} )

    then use it like this:

    import {firestore} from 'some/place'

...

// you can now have types while setting and getting data
const usersRef = firestore.collection<UserType>('/users')
await userRef.add({
  displayName: 'New User',
  // update
  createdAt: firestore.fieldValue.serverTimestamp(),
  friends: firestore.fieldValue.arrayUnion('FRIEND_NAME')
})
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