fix files for publishing

.gitignore

@@ -12,6 +12,7 @@ npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
 firebase-debug.log
+ui-debug.log
 .pnpm-debug.log
 
 
@@ -78,9 +79,6 @@ docs/.docusaurus
 docs/providers.json
 
 # Core
-packages/core/*.js
-packages/core/*.d.ts
-packages/core/*.d.ts.map
 packages/core/src/providers/oauth-types.ts
 packages/core/lib
 packages/core/providers
@@ -96,3 +94,7 @@ packages/frameworks-sveltekit/.svelte-kit
 packages/frameworks-sveltekit/package
 packages/frameworks-sveltekit/vite.config.js.timestamp-*
 packages/frameworks-sveltekit/vite.config.ts.timestamp-*
+
+# Adapters
+
+docs/docs/reference/adapter

docs/docs/guides/03-basics/refresh-token-rotation.md

@@ -22,7 +22,7 @@ Using a JWT to store the `refresh_token` is less secure than saving it in a data
 
 #### JWT strategy
 
-Using the [jwt](../../reference/core/interfaces/types.CallbacksOptions.md#jwt) and [session](../../reference/core/interfaces/types.CallbacksOptions.md#session) callbacks, we can persist OAuth tokens and refresh them when they expire.
+Using the [jwt](../../reference/core/types#jwt) and [session](../../reference/core/types#session) callbacks, we can persist OAuth tokens and refresh them when they expire.
 
 Below is a sample implementation using Google's Identity Provider. Please note that the OAuth 2.0 request in the `refreshAccessToken()` function will vary between different providers, but the core logic should remain similar.
 

docs/docs/reference/06-adapters/firebase.md

@@ -1,75 +0,0 @@
----
-id: firebase
-title: Firebase
----
-
-:::warning
-This adapter is still experimental and does not work with Auth.js 4 or newer. If you would like to help out upgrading it, please visit [this PR](https://github.com/nextauthjs/next-auth/pull/3873)
-:::
-
-This is the Firebase Adapter for [`next-auth`](https://authjs.dev). This package can only be used in conjunction with the primary `next-auth` package. It is not a standalone package.
-
-## Getting Started
-
-1. Install the necessary packages
-
-```bash npm2yarn
-npm install next-auth @next-auth/firebase-adapter@experimental
-```
-
-2. Add this adapter to your `pages/api/auth/[...nextauth].js` next-auth configuration object.
-
-```javascript title="pages/api/auth/[...nextauth].js"
-import NextAuth from "next-auth"
-import GoogleProvider from "next-auth/providers/google"
-import { FirebaseAdapter } from "@next-auth/firebase-adapter"
-
-import firebase from "firebase/app"
-import "firebase/firestore"
-
-const firestore = (
-  firebase.apps[0] ?? firebase.initializeApp(/* your config */)
-).firestore()
-
-// For more information on each option (and a full list of options) go to
-// https://authjs.dev/reference/configuration/auth-options
-export default NextAuth({
-  // https://authjs.dev/reference/providers/
-  providers: [
-    GoogleProvider({
-      clientId: process.env.GOOGLE_ID,
-      clientSecret: process.env.GOOGLE_SECRET,
-    }),
-  ],
-  adapter: FirebaseAdapter(firestore),
-  ...
-})
-```
-
-## Options
-
-When initializing the firestore adapter, you must pass in the firebase config object with the details from your project. More details on how to obtain that config object can be found [here](https://support.google.com/firebase/answer/7015592).
-
-An example firebase config looks like this:
-
-```js
-const firebaseConfig = {
-  apiKey: "AIzaSyDOCAbC123dEf456GhI789jKl01-MnO",
-  authDomain: "myapp-project-123.firebaseapp.com",
-  databaseURL: "https://myapp-project-123.firebaseio.com",
-  projectId: "myapp-project-123",
-  storageBucket: "myapp-project-123.appspot.com",
-  messagingSenderId: "65211879809",
-  appId: "1:65211879909:web:3ae38ef1cdcb2e01fe5f0c",
-  measurementId: "G-8GSGZQ44ST",
-}
-```
-
-See [firebase.google.com/docs/web/setup](https://firebase.google.com/docs/web/setup) for more details.
-
-:::tip **From Firebase**
-
-**Caution**: We do not recommend manually modifying an app's Firebase config file or object. If you initialize an app with invalid or missing values for any of these required "Firebase options", then your end users may experience serious issues.
-
-For open source projects, we generally do not recommend including the app's Firebase config file or object in source control because, in most cases, your users should create their own Firebase projects and point their apps to their own Firebase resources (via their own Firebase config file or object).
-:::

docs/docusaurus.config.js

@@ -226,6 +226,21 @@ const docusaurusConfig = {
         },
       },
     ],
+    [
+      "docusaurus-plugin-typedoc",
+      {
+        ...typedocConfig,
+        id: "firebase-adapter",
+        plugin: [require.resolve("./typedoc-mdn-links")],
+        watch: process.env.TYPEDOC_WATCH,
+        entryPoints: ["../packages/adapter-firebase/src/index.ts"],
+        tsconfig: "../packages/adapter-firebase/tsconfig.json",
+        out: "reference/adapter/firebase",
+        sidebar: {
+          indexLabel: "Firebase",
+        },
+      },
+    ],
   ],
 }
 

docs/sidebars.js

@@ -50,12 +50,8 @@ module.exports = {
       label: "Database Adapters",
       link: { type: "doc", id: "reference/adapters/overview" },
       items: [
-        {
-          type: "autogenerated",
-          dirName: "reference/06-adapters",
-          // See: https://github.com/facebook/docusaurus/issues/5689
-          // exclude: ["index"],
-        },
+        { type: "doc", id: "reference/adapter/firebase/index" },
+        { type: "autogenerated", dirName: "reference/06-adapters" },
       ],
     },
     {

packages/adapter-firebase/.firebaserc

@@ -1 +0,0 @@
-{}

packages/adapter-firebase/CHANGELOG.md

@@ -1,16 +0,0 @@
-# Change Log
-
-All notable changes to this project will be documented in this file.
-See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
-
-## [0.1.3](https://github.com/nextauthjs/adapters/compare/@next-auth/firebase-adapter@0.1.2...@next-auth/firebase-adapter@0.1.3) (2021-08-17)
-
-**Note:** Version bump only for package @next-auth/firebase-adapter
-
-## [0.1.2](https://github.com/nextauthjs/adapters/compare/@next-auth/firebase-adapter@0.1.1...@next-auth/firebase-adapter@0.1.2) (2021-07-02)
-
-**Note:** Version bump only for package @next-auth/firebase-adapter
-
-## [0.1.1](https://github.com/nextauthjs/adapters/compare/@next-auth/firebase-adapter@0.1.0...@next-auth/firebase-adapter@0.1.1) (2021-06-30)
-
-**Note:** Version bump only for package @next-auth/firebase-adapter

packages/adapter-firebase/README.md

@@ -1,8 +1,8 @@
 <p align="center">
    <br/>
    <a href="https://authjs.dev" target="_blank">
-    <img height="64px" src="https://authjs.dev/img/logo/logo-sm.png" /></a><img height="64px" src="https://raw.githubusercontent.com/nextauthjs/adapters/main/packages/firebase/logo.svg" />
-   <h3 align="center"><b>Firebase Adapter</b> - NextAuth.js</h3>
+    <img height="64px" src="https://authjs.dev/img/logo/logo-sm.png" /></a><img height="64px" src="https://raw.githubusercontent.com/nextauthjs/next-auth/main/packages/adapter-firebase/logo.svg" />
+   <h3 align="center"><b>Firebase Adapter</b> - Auth.js</h3>
    <p align="center">
    Open Source. Full Stack. Own Your Data.
    </p>
@@ -13,72 +13,12 @@
    </p>
 </p>
 
-## Overview
 
-This is the Firebase Adapter for [`auth.js`](https://authjs.dev). This package can only be used in conjunction with the primary `next-auth` package. It is not a standalone package.
+This is the official Firebase Adapter for [Auth.js](https://authjs.dev) / [NextAuth.js](https://next-auth.js.org/), using the [Firebase Admin SDK](https://firebase.google.com/docs/admin/setup) and [Firestore](https://firebase.google.com/docs/firestore).
 
-You can find more Firebase information in the docs at [authjs.dev/reference/adapters/firebase](https://authjs.dev/reference/adapters/firebase).
+## Documentation
 
-## Getting Started
-
-1. Install `next-auth` and `@next-auth/firebase-adapter`.
-
-```js
-npm install next-auth @next-auth/firebase-adapter
-```
-
-2. Add this adapter to your `pages/api/[...nextauth].js` next-auth configuration object.
-
-```js
-import NextAuth from "next-auth"
-import Providers from "next-auth/providers"
-import { FirestoreAdapter } from "@next-auth/firebase-adapter"
-
-import { initializeApp } from "firebase/app";
-import { getFirestore } from "firebase/firestore"
-
-const app = initializeApp({ projectId: "next-auth-test" });
-const firestore = getFirestore(app);
-
-// For more information on each option (and a full list of options) go to
-// https://authjs.dev/reference/configuration/auth-options
-export default NextAuth({
-  // https://authjs.dev/reference/providers/oauth-builtin
-  providers: [
-    Providers.Google({
-      clientId: process.env.GOOGLE_ID,
-      clientSecret: process.env.GOOGLE_SECRET,
-    }),
-  ],
-  adapter: FirestoreAdapter(firestore),
-  ...
-})
-```
-
-## Options
-
-When initializing the firestore adapter, you must pass in the firebase config object with the details from your project. More details on how to obtain that config object can be found [here](https://support.google.com/firebase/answer/7015592).
-
-An example firebase config looks like this:
-
-```js
-const firebaseConfig = {
-  apiKey: "AIzaSyDOCAbC123dEf456GhI789jKl01-MnO",
-  authDomain: "myapp-project-123.firebaseapp.com",
-  databaseURL: "https://myapp-project-123.firebaseio.com",
-  projectId: "myapp-project-123",
-  storageBucket: "myapp-project-123.appspot.com",
-  messagingSenderId: "65211879809",
-  appId: "1:65211879909:web:3ae38ef1cdcb2e01fe5f0c",
-  measurementId: "G-8GSGZQ44ST",
-}
-```
-
-See [firebase.google.com/docs/web/setup](https://firebase.google.com/docs/web/setup) for more details.
-
-> **From Firebase - Caution**: We do not recommend manually modifying an app's Firebase config file or object. If you initialize an app with invalid or missing values for any of these required "Firebase options", then your end users may experience serious issues.
->
-> For open source projects, we generally do not recommend including the app's Firebase config file or object in source control because, in most cases, your users should create their own Firebase projects and point their apps to their own Firebase resources (via their own Firebase config file or object).
+Check out the [documentation](https://authjs.dev/reference/adapter/firebase) to learn how to use this adapter in your project.
 
 ## Contributing
 

packages/adapter-firebase/firebase.json

@@ -1,5 +1,8 @@
 {
-  "emulators": {
+  "firestore": {
+    "rules": "firestore.rules"
+  },
+  "emulator": {
     "firestore": {
       "port": 8080
     }

packages/adapter-firebase/firestore.rules

@@ -0,0 +1,10 @@
+rules_version = '2';
+
+// Deny read/write access to all users under any conditions
+service cloud.firestore {
+  match /databases/{database}/documents {
+    match /{document=**} {
+      allow read, write: if false;
+    }
+  }
+}

packages/adapter-firebase/jest.config.js

@@ -1 +0,0 @@
-module.exports = require("@next-auth/adapter-test/jest/jest-preset")

packages/adapter-firebase/logo.svg

@@ -33,4 +33,4 @@
     <circle cx="144" cy="144" r="40" fill="#757575"/>
     <path d="M144 146l-18 8v-8l18-8 18 8v7-1.5 2.5zm0-22l18 8v8l-18-8-18 8v-8zm6.75 29l9 4-15.75 7v-8z" fill="#fff" fill-rule="evenodd"/>
   </g>
-</svg>
+</svg>

packages/adapter-firebase/package.json

@@ -12,35 +12,44 @@
     "Nico Domino <yo@ndo.dev>",
     "Alex Meuer <github@alexmeuer.com>"
   ],
-  "main": "dist/index.js",
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./index.d.ts",
+      "import": "./index.js"
+    }
+  },
   "files": [
-    "dist",
-    "index.d.ts"
+    "src",
+    "*.js",
+    "*.d.ts*"
   ],
   "license": "ISC",
   "keywords": [
     "next-auth",
     "next.js",
-    "firebase"
+    "firebase",
+    "firebase-admin"
   ],
   "private": false,
   "publishConfig": {
     "access": "public"
   },
   "scripts": {
+    "dev": "tsc -w",
     "build": "tsc",
-    "test": "FIRESTORE_EMULATOR_HOST=localhost:8080 firebase --token '$FIREBASE_TOKEN' emulators:exec --only firestore --project next-auth-test jest"
+    "test": "firebase emulators:exec --only firestore --project next-auth-test 'jest -c tests/jest.config.js'"
   },
   "peerDependencies": {
-    "firebase": "^9.7.0",
+    "firebase-admin": "^11.4.1",
     "next-auth": "^4"
   },
   "devDependencies": {
     "@next-auth/adapter-test": "workspace:*",
     "@next-auth/tsconfig": "workspace:*",
-    "firebase": "^9.14.0",
+    "firebase-admin": "^11.4.1",
     "firebase-tools": "^11.16.1",
-    "jest": "^27.4.3",
+    "jest": "^29.3.1",
     "next-auth": "workspace:*"
   }
 }

packages/adapter-firebase/src/converter.ts

@@ -1,58 +0,0 @@
-import { Timestamp } from "firebase/firestore"
-import type {
-  FirestoreDataConverter,
-  QueryDocumentSnapshot,
-  WithFieldValue,
-} from "firebase/firestore"
-
-const isTimestamp = (value: unknown): value is Timestamp =>
-  typeof value === "object" && value !== null && value instanceof Timestamp
-
-interface GetConverterOptions {
-  excludeId?: boolean
-}
-
-export const getConverter = <Document extends Record<string, unknown>>(
-  options?: GetConverterOptions
-): FirestoreDataConverter<Document> => ({
-  // `PartialWithFieldValue` implicitly types `object` as `any`, so we want to explicitly type it
-  toFirestore(object: WithFieldValue<Document>) {
-    const document: Record<string, unknown> = {}
-
-    Object.keys(object).forEach((key) => {
-      if (object[key] !== undefined) {
-        document[key] = object[key]
-      }
-    })
-
-    return document
-  },
-  // We need to explicitly type `snapshot` since it uses `DocumentData` for generic type
-  fromFirestore(snapshot: QueryDocumentSnapshot<Document>) {
-    if (!snapshot.exists()) {
-      return snapshot
-    }
-
-    let document: Document = snapshot.data()
-
-    if (!options?.excludeId) {
-      document = {
-        ...document,
-        id: snapshot.id,
-      }
-    }
-
-    for (const key in document) {
-      const value = document[key]
-
-      if (isTimestamp(value)) {
-        document = {
-          ...document,
-          [key]: value.toDate(),
-        }
-      }
-    }
-
-    return document
-  },
-})

packages/adapter-firebase/src/getFirebase.ts

@@ -1,11 +0,0 @@
-import { initializeApp, getApps, FirebaseOptions } from "firebase/app"
-
-export default function getFirebase(firebaseOptions: FirebaseOptions) {
-  const apps = getApps()
-  const app = apps.find((app) => app.name === firebaseOptions.projectId)
-  if (app) {
-    return app
-  } else {
-    return initializeApp(firebaseOptions)
-  }
-}

packages/adapter-firebase/src/index.ts

@@ -1,283 +1,302 @@
-import { initializeApp } from "firebase/app"
-import type { FirebaseOptions } from "firebase/app"
+/**
+ * <div style={{display: "flex", justifyContent: "space-between", alignItems: "center", padding: 16}}>
+ * <span>
+ *  Official <b>Firebase</b> adapter for Auth.js / NextAuth.js,
+ *  using the <a href="https://firebase.google.com/docs/admin/setup">Firebase Admin SDK</a>
+ *  &nbsp;and <a href="https://firebase.google.com/docs/firestore">Firestore</a>.</span>
+ * <a href="https://firebase.google.com/">
+ *   <img style={{display: "block"}} src="https://raw.githubusercontent.com/nextauthjs/next-auth/main/packages/adapter-firebase/logo.svg" height="48" width="48"/>
+ * </a>
+ * </div>
+ *
+ * ## Installation
+ *
+ * ```bash npm2yarn2pnpm
+ * npm install next-auth @next-auth/firebase-admin-adapter firebase-admin
+ * ```
+ *
+ * ## References
+ * - [`GOOGLE_APPLICATION_CREDENTIALS` environment variable](https://cloud.google.com/docs/authentication/application-default-credentials#GAC)
+ * - [Firebase Admin SDK setup](https://firebase.google.com/docs/admin/setup#initialize-sdk)
+ *
+ * @module @next-auth/firebase-adapter
+ */
+
+import { type AppOptions } from "firebase-admin"
+import { Firestore } from "firebase-admin/firestore"
+
+import type { Adapter, AdapterUser } from "next-auth/adapters"
 import {
-  addDoc,
-  collection,
-  deleteDoc,
-  doc,
+  collestionsFactory,
+  deleteDocs,
+  initFirestore,
   getDoc,
-  getDocs,
-  getFirestore,
-  limit,
-  query,
-  runTransaction,
-  setDoc,
-  where,
-  connectFirestoreEmulator,
-} from "firebase/firestore"
+  getOneDoc,
+  mapFieldsFactory,
+} from "./utils"
 
-import type {
-  Adapter,
-  AdapterUser,
-  AdapterAccount,
-  AdapterSession,
-  VerificationToken,
-} from "next-auth/adapters"
+export { initFirestore } from "./utils"
 
-import { getConverter } from "./converter"
-import getFirebase from "./getFirebase"
-
-export type IndexableObject = Record<string, unknown>
-
-export interface FirestoreAdapterOptions {
-  emulator?: {
-    host?: string
-    port?: number
-  }
+/** Configure the Firebase Adapter. */
+export interface FirebaseAdapterConfig extends AppOptions {
+  /**
+   * The name of the app passed to {@link https://firebase.google.com/docs/reference/admin/node/firebase-admin.md#initializeapp `initializeApp()`}.
+   */
+  name?: string
+  firestore?: Firestore
+  /**
+   * Use this option if mixed `snake_case` and `camelCase` field names in the database is an issue for you.
+   * Passing `snake_case` will convert all field and collection names to `snake_case`.
+   * E.g. the collection `verificationTokens` will be `verification_tokens`,
+   * and fields like `emailVerified` will be `email_verified` instead.
+   *
+   *
+   * @example
+   * ```ts title="pages/api/auth/[...nextauth].ts"
+   * import NextAuth from "next-auth"
+   * import { FirestoreAdapter } from "@next-auth/firebase-adapter"
+   *
+   * export default NextAuth({
+   *  adapter: FirestoreAdapter({ namingStrategy: "snake_case" })
+   *  // ...
+   * })
+   * ```
+   */
+  namingStrategy?: "snake_case"
 }
 
-export function FirestoreAdapter({
-  emulator,
-  ...firebaseOptions
-}: FirebaseOptions & FirestoreAdapterOptions): Adapter {
-  const firebaseApp = getFirebase(firebaseOptions)
-  const db = getFirestore(firebaseApp)
+/**
+ * #### Usage
+ *
+ * First, create a Firebase project and generate a service account key.
+ * Visit: `https://console.firebase.google.com/u/0/project/{project-id}/settings/serviceaccounts/adminsdk` (replace `{project-id}` with your project's id)
+ *
+ * Now you have a few options to authenticate with the Firebase Admin SDK in your app:
+ *
+ * ##### 1. `GOOGLE_APPLICATION_CREDENTIALS` environment variable:
+ *  - Download the service account key and save it in your project. (Make sure to add the file to your `.gitignore`!)
+ *  - Add [`GOOGLE_APPLICATION_CREDENTIALS`](https://cloud.google.com/docs/authentication/application-default-credentials#GAC) to your environment variables and point it to the service account key file.
+ *  - The adapter will automatically pick up the environment variable and use it to authenticate with the Firebase Admin SDK.
+ *
+ * @example
+ * ```ts title="pages/api/auth/[...nextauth].ts"
+ * import NextAuth from "next-auth"
+ * import { FirestoreAdapter } from "@next-auth/firebase-adapter"
+ *
+ * export default NextAuth({
+ *   adapter: FirestoreAdapter(),
+ *   // ...
+ * })
+ * ```
+ *
+ * ##### 2. Service account values as environment variables
+ *
+ * - Download the service account key to a temporary location. (Make sure to not commit this file to your repository!)
+ * - Add the following environment variables to your project: `FIREBASE_PROJECT_ID`, `FIREBASE_CLIENT_EMAIL`, `FIREBASE_PRIVATE_KEY`.
+ * - Pass the config to the adapter, using the environment variables as shown in the example below.
+ *
+ * @example
+ * ```ts title="pages/api/auth/[...nextauth].ts"
+ * import NextAuth from "next-auth"
+ * import { FirestoreAdapter } from "@next-auth/firebase-adapter"
+ * import { cert } from "firebase-admin/app"
+ *
+ * export default NextAuth({
+ *  adapter: FirestoreAdapter({
+ *    credential: cert({
+ *      projectId: process.env.FIREBASE_PROJECT_ID,
+ *      clientEmail: process.env.FIREBASE_CLIENT_EMAIL,
+ *      privateKey: process.env.FIREBASE_PRIVATE_KEY,
+ *    })
+ *  })
+ *  // ...
+ * })
+ * ```
+ *
+ * ##### 3. Use an existing Firestore instance
+ *
+ * If you already have a Firestore instance, you can pass that to the adapter directly instead.
+ *
+ * :::note
+ * When passing an instance and in a serverless environment, remember to handle duplicate app initialization.
+ * :::
+ *
+ * :::tip
+ * You can use the {@link initFirestore} utility to initialize the app and get an instance safely.
+ * :::
+ *
+ * @example
+ * ```ts title="pages/api/auth/[...nextauth].ts"
+ * import NextAuth from "next-auth"
+ * import { FirestoreAdapter } from "@next-auth/firebase-adapter"
+ * import { firestore } from "lib/firestore"
+ *
+ * export default NextAuth({
+ *  adapter: FirestoreAdapter(firestore),
+ *  // ...
+ * })
+ * ```
+ */
+export function FirestoreAdapter(
+  config?: FirebaseAdapterConfig | Firestore
+): Adapter {
+  const { db, namingStrategy = "default" } =
+    config instanceof Firestore
+      ? { db: config }
+      : { ...config, db: config?.firestore ?? initFirestore(config) }
 
-  if (emulator) {
-    connectFirestoreEmulator(
-      db,
-      emulator?.host ?? "localhost",
-      emulator?.port ?? 3001
-    )
-  }
-
-  const Users = collection(db, "users").withConverter(
-    getConverter<AdapterUser & IndexableObject>()
-  )
-  const Sessions = collection(db, "sessions").withConverter(
-    getConverter<AdapterSession & IndexableObject>()
-  )
-  const Accounts = collection(db, "accounts").withConverter(
-    getConverter<AdapterAccount>()
-  )
-  const VerificationTokens = collection(db, "verificationTokens").withConverter(
-    getConverter<VerificationToken & IndexableObject>({ excludeId: true })
-  )
+  const preferSnakeCase = namingStrategy === "snake_case"
+  const C = collestionsFactory(db, preferSnakeCase)
+  const mapper = mapFieldsFactory(preferSnakeCase)
 
   return {
-    async createUser(newUser) {
-      const userRef = await addDoc(Users, newUser)
-      const userSnapshot = await getDoc(userRef)
+    async createUser(userInit) {
+      const { id: userId } = await C.users.add(userInit as AdapterUser)
 
-      if (userSnapshot.exists() && Users.converter) {
-        return Users.converter.fromFirestore(userSnapshot)
-      }
+      const user = await getDoc(C.users.doc(userId))
+      if (!user) throw new Error("[createUser] Failed to fetch created user")
 
-      throw new Error("[createUser] Failed to create user")
+      return user
     },
+
     async getUser(id) {
-      const userSnapshot = await getDoc(doc(Users, id))
-
-      if (userSnapshot.exists() && Users.converter) {
-        return Users.converter.fromFirestore(userSnapshot)
-      }
-
-      return null
+      return await getDoc(C.users.doc(id))
     },
+
     async getUserByEmail(email) {
-      const userQuery = query(Users, where("email", "==", email), limit(1))
-      const userSnapshots = await getDocs(userQuery)
-      const userSnapshot = userSnapshots.docs[0]
-
-      if (userSnapshot?.exists() && Users.converter) {
-        return Users.converter.fromFirestore(userSnapshot)
-      }
-
-      return null
+      return await getOneDoc(C.users.where("email", "==", email))
     },
+
     async getUserByAccount({ provider, providerAccountId }) {
-      const accountQuery = query(
-        Accounts,
-        where("provider", "==", provider),
-        where("providerAccountId", "==", providerAccountId),
-        limit(1)
+      const account = await getOneDoc(
+        C.accounts
+          .where("provider", "==", provider)
+          .where(mapper.toDb("providerAccountId"), "==", providerAccountId)
       )
-      const accountSnapshots = await getDocs(accountQuery)
-      const accountSnapshot = accountSnapshots.docs[0]
+      if (!account) return null
 
-      if (accountSnapshot?.exists()) {
-        const { userId } = accountSnapshot.data()
-        const userDoc = await getDoc(doc(Users, userId))
-
-        if (userDoc.exists() && Users.converter) {
-          return Users.converter.fromFirestore(userDoc)
-        }
-      }
-
-      return null
+      return await getDoc(C.users.doc(account.userId))
     },
 
     async updateUser(partialUser) {
-      const userRef = doc(Users, partialUser.id)
+      if (!partialUser.id) throw new Error("[updateUser] Missing id")
 
-      await setDoc(userRef, partialUser, { merge: true })
+      const userRef = C.users.doc(partialUser.id)
 
-      const userSnapshot = await getDoc(userRef)
+      await userRef.set(partialUser, { merge: true })
 
-      if (userSnapshot.exists() && Users.converter) {
-        return Users.converter.fromFirestore(userSnapshot)
-      }
+      const user = await getDoc(userRef)
+      if (!user) throw new Error("[updateUser] Failed to fetch updated user")
 
-      throw new Error("[updateUser] Failed to update user")
+      return user
     },
 
     async deleteUser(userId) {
-      const userRef = doc(Users, userId)
-      const accountsQuery = query(Accounts, where("userId", "==", userId))
-      const sessionsQuery = query(Sessions, where("userId", "==", userId))
+      await db.runTransaction(async (transaction) => {
+        const accounts = await C.accounts
+          .where(mapper.toDb("userId"), "==", userId)
+          .get()
+        const sessions = await C.sessions
+          .where(mapper.toDb("userId"), "==", userId)
+          .get()
 
-      // TODO: May be better to use events instead of transactions?
-      await runTransaction(db, async (transaction) => {
-        const accounts = await getDocs(accountsQuery)
-        const sessions = await getDocs(sessionsQuery)
+        transaction.delete(C.users.doc(userId))
 
-        transaction.delete(userRef)
         accounts.forEach((account) => transaction.delete(account.ref))
         sessions.forEach((session) => transaction.delete(session.ref))
       })
     },
 
-    async linkAccount(account) {
-      const accountRef = await addDoc(Accounts, account)
-      const accountSnapshot = await getDoc(accountRef)
-
-      if (accountSnapshot.exists() && Accounts.converter) {
-        return Accounts.converter.fromFirestore(accountSnapshot)
-      }
+    async linkAccount(accountInit) {
+      const ref = await C.accounts.add(accountInit)
+      const account = await ref.get().then((doc) => doc.data())
+      return account ?? null
     },
 
     async unlinkAccount({ provider, providerAccountId }) {
-      const accountQuery = query(
-        Accounts,
-        where("provider", "==", provider),
-        where("providerAccountId", "==", providerAccountId),
-        limit(1)
+      await deleteDocs(
+        C.accounts
+          .where("provider", "==", provider)
+          .where(mapper.toDb("providerAccountId"), "==", providerAccountId)
+          .limit(1)
       )
-      const accountSnapshots = await getDocs(accountQuery)
-      const accountSnapshot = accountSnapshots.docs[0]
-
-      if (accountSnapshot?.exists()) {
-        await deleteDoc(accountSnapshot.ref)
-      }
     },
 
-    async createSession(session) {
-      const sessionRef = await addDoc(Sessions, session)
-      const sessionSnapshot = await getDoc(sessionRef)
+    async createSession(sessionInit) {
+      const ref = await C.sessions.add(sessionInit)
+      const session = await ref.get().then((doc) => doc.data())
 
-      if (sessionSnapshot.exists() && Sessions.converter) {
-        return Sessions.converter.fromFirestore(sessionSnapshot)
-      }
+      if (session) return session ?? null
 
-      throw new Error("[createSession] Failed to create session")
+      throw new Error("[createSession] Failed to fetch created session")
     },
 
     async getSessionAndUser(sessionToken) {
-      const sessionQuery = query(
-        Sessions,
-        where("sessionToken", "==", sessionToken),
-        limit(1)
+      const session = await getOneDoc(
+        C.sessions.where(mapper.toDb("sessionToken"), "==", sessionToken)
       )
-      const sessionSnapshots = await getDocs(sessionQuery)
-      const sessionSnapshot = sessionSnapshots.docs[0]
+      if (!session) return null
 
-      if (sessionSnapshot?.exists() && Sessions.converter) {
-        const session = Sessions.converter.fromFirestore(sessionSnapshot)
-        const userDoc = await getDoc(doc(Users, session.userId))
+      const user = await getDoc(C.users.doc(session.userId))
+      if (!user) return null
 
-        if (userDoc.exists() && Users.converter) {
-          const user = Users.converter.fromFirestore(userDoc)
-
-          return { session, user }
-        }
-      }
-
-      return null
+      return { session, user }
     },
 
     async updateSession(partialSession) {
-      const sessionQuery = query(
-        Sessions,
-        where("sessionToken", "==", partialSession.sessionToken),
-        limit(1)
-      )
-      const sessionSnapshots = await getDocs(sessionQuery)
-      const sessionSnapshot = sessionSnapshots.docs[0]
+      const sessionId = await db.runTransaction(async (transaction) => {
+        const sessionSnapshot = (
+          await transaction.get(
+            C.sessions
+              .where(
+                mapper.toDb("sessionToken"),
+                "==",
+                partialSession.sessionToken
+              )
+              .limit(1)
+          )
+        ).docs[0]
+        if (!sessionSnapshot?.exists) return null
 
-      if (sessionSnapshot?.exists()) {
-        await setDoc(sessionSnapshot.ref, partialSession, { merge: true })
+        transaction.set(sessionSnapshot.ref, partialSession, { merge: true })
 
-        const sessionDoc = await getDoc(sessionSnapshot.ref)
+        return sessionSnapshot.id
+      })
 
-        if (sessionDoc?.exists() && Sessions.converter) {
-          const session = Sessions.converter.fromFirestore(sessionDoc)
+      if (!sessionId) return null
 
-          return session
-        }
-      }
-
-      return null
+      const session = await getDoc(C.sessions.doc(sessionId))
+      if (session) return session
+      throw new Error("[updateSession] Failed to fetch updated session")
     },
 
     async deleteSession(sessionToken) {
-      const sessionQuery = query(
-        Sessions,
-        where("sessionToken", "==", sessionToken),
-        limit(1)
+      await deleteDocs(
+        C.sessions
+          .where(mapper.toDb("sessionToken"), "==", sessionToken)
+          .limit(1)
       )
-      const sessionSnapshots = await getDocs(sessionQuery)
-      const sessionSnapshot = sessionSnapshots.docs[0]
-
-      if (sessionSnapshot?.exists()) {
-        await deleteDoc(sessionSnapshot.ref)
-      }
     },
 
     async createVerificationToken(verificationToken) {
-      const verificationTokenRef = await addDoc(
-        VerificationTokens,
-        verificationToken
-      )
-      const verificationTokenSnapshot = await getDoc(verificationTokenRef)
-
-      if (verificationTokenSnapshot.exists() && VerificationTokens.converter) {
-        const { id, ...verificationToken } =
-          VerificationTokens.converter.fromFirestore(verificationTokenSnapshot)
-
-        return verificationToken
-      }
+      await C.verification_tokens.add(verificationToken)
+      return verificationToken
     },
 
     async useVerificationToken({ identifier, token }) {
-      const verificationTokensQuery = query(
-        VerificationTokens,
-        where("identifier", "==", identifier),
-        where("token", "==", token),
-        limit(1)
-      )
-      const verificationTokenSnapshots = await getDocs(verificationTokensQuery)
-      const verificationTokenSnapshot = verificationTokenSnapshots.docs[0]
+      const verificationTokenSnapshot = (
+        await C.verification_tokens
+          .where("identifier", "==", identifier)
+          .where("token", "==", token)
+          .limit(1)
+          .get()
+      ).docs[0]
 
-      if (verificationTokenSnapshot?.exists() && VerificationTokens.converter) {
-        await deleteDoc(verificationTokenSnapshot.ref)
+      if (!verificationTokenSnapshot) return null
 
-        const { id, ...verificationToken } =
-          VerificationTokens.converter.fromFirestore(verificationTokenSnapshot)
-
-        return verificationToken
-      }
-
-      return null
+      const data = verificationTokenSnapshot.data()
+      await verificationTokenSnapshot.ref.delete()
+      return data
     },
   }
 }

packages/adapter-firebase/src/utils.ts

@@ -0,0 +1,168 @@
+import { AppOptions, getApps, initializeApp } from "firebase-admin/app"
+
+import {
+  getFirestore,
+  initializeFirestore,
+  Timestamp,
+} from "firebase-admin/firestore"
+
+import type {
+  AdapterUser,
+  AdapterAccount,
+  AdapterSession,
+  VerificationToken,
+} from "next-auth/adapters"
+import { FirebaseAdapterConfig } from "."
+
+// for consistency, store all fields as snake_case in the database
+const MAP_TO_FIRESTORE: Record<string, string | undefined> = {
+  userId: "user_id",
+  sessionToken: "session_token",
+  providerAccountId: "provider_account_id",
+  emailVerified: "email_verified",
+}
+const MAP_FROM_FIRESTORE: Record<string, string | undefined> = {}
+
+for (const key in MAP_TO_FIRESTORE) {
+  MAP_FROM_FIRESTORE[MAP_TO_FIRESTORE[key]!] = key
+}
+
+const identity = <T>(x: T) => x
+
+/** @internal */
+export function mapFieldsFactory(preferSnakeCase?: boolean) {
+  if (preferSnakeCase) {
+    return {
+      toDb: (field: string) => MAP_TO_FIRESTORE[field] ?? field,
+      fromDb: (field: string) => MAP_FROM_FIRESTORE[field] ?? field,
+    }
+  }
+  return { toDb: identity, fromDb: identity }
+}
+
+/** @internal */
+export function getConverter<Document extends Record<string, any>>(options: {
+  excludeId?: boolean
+  preferSnakeCase?: boolean
+}): FirebaseFirestore.FirestoreDataConverter<Document> {
+  const mapper = mapFieldsFactory(options?.preferSnakeCase ?? false)
+
+  return {
+    toFirestore(object) {
+      const document: Record<string, unknown> = {}
+
+      for (const key in object) {
+        if (key === "id") continue
+        const value = object[key]
+        if (value !== undefined) {
+          document[mapper.toDb(key)] = value
+        } else {
+          console.warn(`FirebaseAdapter: value for key "${key}" is undefined`)
+        }
+      }
+
+      return document
+    },
+
+    fromFirestore(
+      snapshot: FirebaseFirestore.QueryDocumentSnapshot<Document>
+    ): Document {
+      const document = snapshot.data()! // we can guarentee it exists
+
+      const object: Record<string, unknown> = {}
+
+      if (!options?.excludeId) {
+        object.id = snapshot.id
+      }
+
+      for (const key in document) {
+        let value: any = document[key]
+        if (value instanceof Timestamp) value = value.toDate()
+
+        object[mapper.fromDb(key)] = value
+      }
+
+      return object as Document
+    },
+  }
+}
+
+/** @internal */
+export async function getOneDoc<T>(
+  querySnapshot: FirebaseFirestore.Query<T>
+): Promise<T | null> {
+  const querySnap = await querySnapshot.limit(1).get()
+  return querySnap.docs[0]?.data() ?? null
+}
+
+/** @internal */
+export async function deleteDocs<T>(
+  querySnapshot: FirebaseFirestore.Query<T>
+): Promise<void> {
+  const querySnap = await querySnapshot.get()
+  for (const doc of querySnap.docs) {
+    await doc.ref.delete()
+  }
+}
+
+/** @internal */
+export async function getDoc<T>(
+  docRef: FirebaseFirestore.DocumentReference<T>
+): Promise<T | null> {
+  const docSnap = await docRef.get()
+  return docSnap.data() ?? null
+}
+
+/** @internal */
+export function collestionsFactory(
+  db: FirebaseFirestore.Firestore,
+  preferSnakeCase = false
+) {
+  return {
+    users: db
+      .collection("users")
+      .withConverter(getConverter<AdapterUser>({ preferSnakeCase })),
+    sessions: db
+      .collection("sessions")
+      .withConverter(getConverter<AdapterSession>({ preferSnakeCase })),
+    accounts: db
+      .collection("accounts")
+      .withConverter(getConverter<AdapterAccount>({ preferSnakeCase })),
+    verification_tokens: db
+      .collection(
+        preferSnakeCase ? "verification_tokens" : "verificationTokens"
+      )
+      .withConverter(
+        getConverter<VerificationToken>({ preferSnakeCase, excludeId: true })
+      ),
+  }
+}
+
+/**
+ * Utility function that helps making sure that there is no duplicate app initialization issues in serverless environments.
+ * If no parameter is passed, it will use the `GOOGLE_APPLICATION_CREDENTIALS` environment variable to initialize a Firestore instance.
+ *
+ * @example
+ * ```ts title="lib/firestore.ts"
+ * import { initFirestore } from "@next-auth/firebase-adapter"
+ * import { cert } from "firebase-admin/app"
+ *
+ * export const firestore = initFirestore({
+ *  credential: cert({
+ *    projectId: process.env.FIREBASE_PROJECT_ID,
+ *    clientEmail: process.env.FIREBASE_CLIENT_EMAIL,
+ *    privateKey: process.env.FIREBASE_PRIVATE_KEY,
+ *  })
+ * })
+ * ```
+ */
+export function initFirestore(
+  options: AppOptions & { name?: FirebaseAdapterConfig["name"] } = {}
+) {
+  const apps = getApps()
+  const app = options.name ? apps.find((a) => a.name === options.name) : apps[0]
+
+  if (app) return getFirestore(app)
+
+  return initializeFirestore(initializeApp(options, options.name))
+}

packages/adapter-firebase/tests/index.test.ts

@@ -1,118 +1,57 @@
 import { runBasicTests } from "@next-auth/adapter-test"
-import { FirestoreAdapter } from "../src"
 
+import { FirestoreAdapter, type FirebaseAdapterConfig } from "../src"
 import {
-  getFirestore,
-  connectFirestoreEmulator,
-  terminate,
-  collection,
-  query,
-  where,
-  limit,
-  getDocs,
+  collestionsFactory,
+  initFirestore,
   getDoc,
-  doc,
-} from "firebase/firestore"
-import { initializeApp } from "firebase/app"
-import { getConverter } from "../src/converter"
-import type {
-  AdapterSession,
-  AdapterUser,
-  VerificationToken,
-} from "next-auth/adapters"
-import type { Account } from "next-auth"
+  getOneDoc,
+  mapFieldsFactory,
+} from "../src/utils"
 
-const app = initializeApp({ projectId: "next-auth-test" })
-const firestore = getFirestore(app)
+describe.each([
+  { namingStrategy: "snake_case" },
+  { namingStrategy: "default" },
+] as Partial<FirebaseAdapterConfig>[])(
+  "FirebaseAdapter with config: %s",
+  (config) => {
+    config.name = `next-auth-test-${config.namingStrategy}`
+    config.projectId = "next-auth-test"
+    config.databaseURL = "http://localhost:8080"
 
-connectFirestoreEmulator(firestore, "localhost", 8080)
+    const db = initFirestore(config)
+    const preferSnakeCase = config.namingStrategy === "snake_case"
+    const mapper = mapFieldsFactory(preferSnakeCase)
+    const C = collestionsFactory(db, preferSnakeCase)
 
-type IndexableObject = Record<string, unknown>
+    for (const [name, collection] of Object.entries(C)) {
+      test(`collection "${name}" should be empty`, async () => {
+        expect((await collection.count().get()).data().count).toBe(0)
+      })
+    }
 
-const Users = collection(firestore, "users").withConverter(
-  getConverter<AdapterUser & IndexableObject>()
+    runBasicTests({
+      adapter: FirestoreAdapter(config),
+      db: {
+        disconnect: async () => await db.terminate(),
+        session: (sessionToken) =>
+          getOneDoc(
+            C.sessions.where(mapper.toDb("sessionToken"), "==", sessionToken)
+          ),
+        user: (userId) => getDoc(C.users.doc(userId)),
+        account: ({ provider, providerAccountId }) =>
+          getOneDoc(
+            C.accounts
+              .where("provider", "==", provider)
+              .where(mapper.toDb("providerAccountId"), "==", providerAccountId)
+          ),
+        verificationToken: ({ identifier, token }) =>
+          getOneDoc(
+            C.verification_tokens
+              .where("identifier", "==", identifier)
+              .where("token", "==", token)
+          ),
+      },
+    })
+  }
 )
-const Sessions = collection(firestore, "sessions").withConverter(
-  getConverter<AdapterSession & IndexableObject>()
-)
-const Accounts = collection(firestore, "accounts").withConverter(
-  getConverter<Account>()
-)
-const VerificationTokens = collection(
-  firestore,
-  "verificationTokens"
-).withConverter(
-  getConverter<VerificationToken & IndexableObject>({ excludeId: true })
-)
-
-runBasicTests({
-  adapter: FirestoreAdapter({ projectId: "next-auth-test" }),
-  db: {
-    async disconnect() {
-      await terminate(firestore)
-    },
-    async session(sessionToken) {
-      const snapshotQuery = query(
-        Sessions,
-        where("sessionToken", "==", sessionToken),
-        limit(1)
-      )
-      const snapshots = await getDocs(snapshotQuery)
-      const snapshot = snapshots.docs[0]
-
-      if (snapshot?.exists() && Sessions.converter) {
-        const session = Sessions.converter.fromFirestore(snapshot)
-
-        return session
-      }
-
-      return null
-    },
-    async user(id) {
-      const snapshot = await getDoc(doc(Users, id))
-
-      if (snapshot?.exists() && Users.converter) {
-        const user = Users.converter.fromFirestore(snapshot)
-
-        return user
-      }
-
-      return null
-    },
-    async account({ provider, providerAccountId }) {
-      const snapshotQuery = query(
-        Accounts,
-        where("provider", "==", provider),
-        where("providerAccountId", "==", providerAccountId),
-        limit(1)
-      )
-      const snapshots = await getDocs(snapshotQuery)
-      const snapshot = snapshots.docs[0]
-
-      if (snapshot?.exists() && Accounts.converter) {
-        const account = Accounts.converter.fromFirestore(snapshot)
-
-        return account
-      }
-
-      return null
-    },
-    async verificationToken({ identifier, token }) {
-      const snapshotQuery = query(
-        VerificationTokens,
-        where("identifier", "==", identifier),
-        where("token", "==", token),
-        limit(1)
-      )
-      const snapshots = await getDocs(snapshotQuery)
-      const snapshot = snapshots.docs[0]
-
-      if (snapshot?.exists() && VerificationTokens.converter) {
-        const verificationToken =
-          VerificationTokens.converter.fromFirestore(snapshot)
-
-        return verificationToken
-      }
-    },
-  },
-})

packages/adapter-firebase/tests/jest.config.js

@@ -0,0 +1,11 @@
+import config from "@next-auth/adapter-test/jest/jest-preset.js"
+
+//TODO: update rest of the packages to Jest 29+
+const {testURL, ...rest} = config
+export default {
+  ...rest,
+  testEnvironmentOptions: {
+    url: testURL
+  },
+  rootDir: ".."
+}

packages/adapter-firebase/tsconfig.json

@@ -1,11 +1,23 @@
 {
   "extends": "@next-auth/tsconfig/tsconfig.adapters.json",
   "compilerOptions": {
-    "rootDir": "src",
-    "outDir": "dist",
     "strict": true,
     "noUncheckedIndexedAccess": true,
-    "moduleResolution": "node"
+    "target": "ES2020",
+    "module": "ESNext",
+    "moduleResolution": "node",
+    "outDir": ".",
+    "rootDir": "src",
+    "skipDefaultLibCheck": true,
+    "strictNullChecks": true,
+    "stripInternal": true,
+    "declarationMap": true,
+    "declaration": true
   },
-  "exclude": ["tests", "dist", "jest.config.js"]
-}
+  "include": [
+    "src/**/*"
+  ],
+  "exclude": [
+    "tests"
+  ]
+}

packages/core/src/index.ts

@@ -1,4 +1,8 @@
 /**
+ *
+ * :::warning Experimental
+ * `@auth/core` is under active development.
+ * :::
  *
  * This is the main entry point to the Auth.js library.
  *