From 7af6ecddeed130073e3e2c783b9a13229fcecb22 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 14:42:00 -0700
Subject: [PATCH 01/11] abstract SDK_VERSION

---
 packages/app/src/firebaseNamespaceCore.ts     | 10 +++-
 packages/database/index.admin.ts              | 50 +++++++++++++++++++
 packages/database/index.node.ts               | 43 +++-------------
 packages/database/index.ts                    |  7 ++-
 packages/database/package.json                |  1 +
 packages/database/rollup.config.js            |  9 ++++
 .../database/src/core/PersistentConnection.ts |  7 ++-
 packages/database/src/core/version.ts         |  7 +++
 .../src/realtime/WebSocketConnection.ts       |  7 ++-
 9 files changed, 95 insertions(+), 46 deletions(-)
 create mode 100644 packages/database/index.admin.ts
 create mode 100644 packages/database/src/core/version.ts

diff --git a/packages/app/src/firebaseNamespaceCore.ts b/packages/app/src/firebaseNamespaceCore.ts
index 4b6dcdcc9fe..a269406b556 100644
--- a/packages/app/src/firebaseNamespaceCore.ts
+++ b/packages/app/src/firebaseNamespaceCore.ts
@@ -29,7 +29,7 @@ import {
   FirebaseServiceNamespace,
   AppHook
 } from '@firebase/app-types/private';
-import { deepExtend, contains } from '@firebase/util';
+import { deepExtend, contains, CONSTANTS } from '@firebase/util';
 import { FirebaseAppImpl } from './firebaseApp';
 import { ERROR_FACTORY, AppError } from './errors';
 import { FirebaseAppLiteImpl } from './lite/firebaseAppLite';
@@ -70,6 +70,14 @@ export function createFirebaseNamespaceCore(
     }
   };
 
+  // setting version on CONSTANTS, so @firebase/database can get the version from 
+  // @firebase/util instead of @firebase/app. So we can provide a special build target
+  // for @firebase/database that has no dependency on @firebase/app. The special build target will
+  // be used by firebase-admin. It is to solve a version conflict (@firebase/app) that could happen 
+  // when firebase and firebase-admin are used in the same project.
+  // https://github.com/firebase/firebase-js-sdk/issues/1696#issuecomment-501546596
+  CONSTANTS.SDK_VERSION = version;
+
   // Inject a circular default export to allow Babel users who were previously
   // using:
   //
diff --git a/packages/database/index.admin.ts b/packages/database/index.admin.ts
new file mode 100644
index 00000000000..5af339b488f
--- /dev/null
+++ b/packages/database/index.admin.ts
@@ -0,0 +1,50 @@
+import { CONSTANTS } from '@firebase/util';
+import { FirebaseApp } from '@firebase/app-types';
+import { _FirebaseNamespace } from '@firebase/app-types/private';
+import { Database } from './src/api/Database';
+import { DataSnapshot } from './src/api/DataSnapshot';
+import { Query } from './src/api/Query';
+import { Reference } from './src/api/Reference';
+import { enableLogging } from './src/core/util/util';
+import { RepoManager } from './src/core/RepoManager';
+import * as INTERNAL from './src/api/internal';
+import * as TEST_ACCESS from './src/api/test_access';
+import './src/nodePatches';
+import { setSDKVersion } from './src/core/version';
+
+/**
+ * A one off register function which returns a database based on the app and
+ * passed database URL.
+ *
+ * @param app A valid FirebaseApp-like object
+ * @param url A valid Firebase databaseURL
+ */
+
+const ServerValue = Database.ServerValue;
+
+export function initStandalone(
+  app: FirebaseApp,
+  url: string,
+  version: string
+) {
+  /**
+   * This should allow the firebase-admin package to provide a custom version
+   * to the backend
+   */
+  CONSTANTS.NODE_ADMIN = true;
+  setSDKVersion(version);
+
+  return {
+    instance: RepoManager.getInstance().databaseFromApp(app, url),
+    namespace: {
+      Reference,
+      Query,
+      Database,
+      DataSnapshot,
+      enableLogging,
+      INTERNAL,
+      ServerValue,
+      TEST_ACCESS
+    }
+  };
+}
\ No newline at end of file
diff --git a/packages/database/index.node.ts b/packages/database/index.node.ts
index 71bcfa964ea..55cf64c08b0 100644
--- a/packages/database/index.node.ts
+++ b/packages/database/index.node.ts
@@ -16,8 +16,7 @@
  */
 
 import firebase from '@firebase/app';
-import { CONSTANTS, isNodeSdk } from '@firebase/util';
-import { FirebaseApp, FirebaseNamespace } from '@firebase/app-types';
+import { FirebaseNamespace } from '@firebase/app-types';
 import { _FirebaseNamespace } from '@firebase/app-types/private';
 import { Database } from './src/api/Database';
 import { DataSnapshot } from './src/api/DataSnapshot';
@@ -29,6 +28,7 @@ import * as INTERNAL from './src/api/internal';
 import * as TEST_ACCESS from './src/api/test_access';
 import './src/nodePatches';
 import * as types from '@firebase/database-types';
+import { setSDKVersion } from './src/core/version';
 
 /**
  * A one off register function which returns a database based on the app and
@@ -40,38 +40,13 @@ import * as types from '@firebase/database-types';
 
 const ServerValue = Database.ServerValue;
 
-export function initStandalone(
-  app: FirebaseApp,
-  url: string,
-  version?: string
-) {
-  /**
-   * This should allow the firebase-admin package to provide a custom version
-   * to the backend
-   */
-  CONSTANTS.NODE_ADMIN = true;
-  if (version) {
-    firebase.SDK_VERSION = version;
-  }
-
-  return {
-    instance: RepoManager.getInstance().databaseFromApp(app, url),
-    namespace: {
-      Reference,
-      Query,
-      Database,
-      DataSnapshot,
-      enableLogging,
-      INTERNAL,
-      ServerValue,
-      TEST_ACCESS
-    }
-  };
-}
-
 export function registerDatabase(instance: FirebaseNamespace) {
+  
+  // set SDK_VERSION
+  setSDKVersion(firebase.SDK_VERSION);
+
   // Register the Database Service with the 'firebase' namespace.
-  const namespace = (instance as _FirebaseNamespace).INTERNAL.registerService(
+  (instance as _FirebaseNamespace).INTERNAL.registerService(
     'database',
     (app, unused, url) => RepoManager.getInstance().databaseFromApp(app, url),
     // firebase.database namespace properties
@@ -88,10 +63,6 @@ export function registerDatabase(instance: FirebaseNamespace) {
     null,
     true
   );
-
-  if (isNodeSdk()) {
-    module.exports = Object.assign({}, namespace, { initStandalone });
-  }
 }
 
 registerDatabase(firebase);
diff --git a/packages/database/index.ts b/packages/database/index.ts
index 5039eb0c6ae..5de3b8bb385 100644
--- a/packages/database/index.ts
+++ b/packages/database/index.ts
@@ -16,7 +16,7 @@
  */
 
 import firebase from '@firebase/app';
-import { FirebaseApp, FirebaseNamespace } from '@firebase/app-types';
+import { FirebaseNamespace } from '@firebase/app-types';
 import { _FirebaseNamespace } from '@firebase/app-types/private';
 import { Database } from './src/api/Database';
 import { DataSnapshot } from './src/api/DataSnapshot';
@@ -28,10 +28,15 @@ import * as INTERNAL from './src/api/internal';
 import * as TEST_ACCESS from './src/api/test_access';
 import { isNodeSdk } from '@firebase/util';
 import * as types from '@firebase/database-types';
+import { setSDKVersion } from './src/core/version';
 
 const ServerValue = Database.ServerValue;
 
 export function registerDatabase(instance: FirebaseNamespace) {
+  
+  // set SDK_VERSION
+  setSDKVersion(firebase.SDK_VERSION);
+  
   // Register the Database Service with the 'firebase' namespace.
   const namespace = (instance as _FirebaseNamespace).INTERNAL.registerService(
     'database',
diff --git a/packages/database/package.json b/packages/database/package.json
index 6b88211f952..fe04070a22c 100644
--- a/packages/database/package.json
+++ b/packages/database/package.json
@@ -7,6 +7,7 @@
   "browser": "dist/index.cjs.js",
   "module": "dist/index.esm.js",
   "esm2017": "dist/index.esm2017.js",
+  "main-admin": "dist/index.admin.node.cjs.js",
   "files": [
     "dist"
   ],
diff --git a/packages/database/rollup.config.js b/packages/database/rollup.config.js
index 365301f11e9..20c09dfecf4 100644
--- a/packages/database/rollup.config.js
+++ b/packages/database/rollup.config.js
@@ -42,6 +42,15 @@ const es5Builds = [
     plugins: es5BuildPlugins,
     external: id => deps.some(dep => id === dep || id.startsWith(`${dep}/`))
   },
+  /**
+   * Node.js Build for firebase-admin (no dep on @firebase/app)
+   */
+  {
+    input: 'index.admin.ts',
+    output: [{ file: pkg['main-admin'], format: 'cjs', sourcemap: true }],
+    plugins: es5BuildPlugins,
+    external: id => deps.some(dep => id === dep || id.startsWith(`${dep}/`))
+  },
   /**
    * Browser Builds
    */
diff --git a/packages/database/src/core/PersistentConnection.ts b/packages/database/src/core/PersistentConnection.ts
index b53c500b989..0c247cecf57 100644
--- a/packages/database/src/core/PersistentConnection.ts
+++ b/packages/database/src/core/PersistentConnection.ts
@@ -15,8 +15,7 @@
  * limitations under the License.
  */
 
-import firebase from '@firebase/app';
-import { contains, isEmpty, safeGet } from '@firebase/util';
+import { contains, isEmpty, safeGet, CONSTANTS } from '@firebase/util';
 import { stringify } from '@firebase/util';
 import { assert } from '@firebase/util';
 import { error, log, logWrapper, warn, ObjectToUniqueKey } from './util/util';
@@ -25,12 +24,12 @@ import { VisibilityMonitor } from './util/VisibilityMonitor';
 import { OnlineMonitor } from './util/OnlineMonitor';
 import { isAdmin, isValidFormat } from '@firebase/util';
 import { Connection } from '../realtime/Connection';
-import { CONSTANTS } from '@firebase/util';
 import { isMobileCordova, isReactNative, isNodeSdk } from '@firebase/util';
 import { ServerActions } from './ServerActions';
 import { AuthTokenProvider } from './AuthTokenProvider';
 import { RepoInfo } from './RepoInfo';
 import { Query } from '../api/Query';
+import { SDK_VERSION } from './version';
 
 const RECONNECT_MIN_DELAY = 1000;
 const RECONNECT_MAX_DELAY_DEFAULT = 60 * 5 * 1000; // 5 minutes in milliseconds (Case: 1858)
@@ -927,7 +926,7 @@ export class PersistentConnection extends ServerActions {
     }
 
     stats[
-      'sdk.' + clientName + '.' + firebase.SDK_VERSION.replace(/\./g, '-')
+      'sdk.' + clientName + '.' + SDK_VERSION.replace(/\./g, '-')
     ] = 1;
 
     if (isMobileCordova()) {
diff --git a/packages/database/src/core/version.ts b/packages/database/src/core/version.ts
new file mode 100644
index 00000000000..f63e9b8619a
--- /dev/null
+++ b/packages/database/src/core/version.ts
@@ -0,0 +1,7 @@
+
+/** The semver (www.semver.org) version of the SDK. */
+export let SDK_VERSION = '';
+
+export function setSDKVersion(version: string): void {
+    SDK_VERSION = version;
+}
diff --git a/packages/database/src/realtime/WebSocketConnection.ts b/packages/database/src/realtime/WebSocketConnection.ts
index 58d9423206d..e6dcc0c5c62 100644
--- a/packages/database/src/realtime/WebSocketConnection.ts
+++ b/packages/database/src/realtime/WebSocketConnection.ts
@@ -19,8 +19,7 @@ import { RepoInfo } from '../core/RepoInfo';
 
 declare const MozWebSocket: any;
 
-import firebase from '@firebase/app';
-import { assert } from '@firebase/util';
+import { assert, CONSTANTS as ENV_CONSTANTS } from '@firebase/util';
 import { logWrapper, splitStringBySize } from '../core/util/util';
 import { StatsManager } from '../core/stats/StatsManager';
 import {
@@ -33,12 +32,12 @@ import {
   VERSION_PARAM,
   WEBSOCKET
 } from './Constants';
-import { CONSTANTS as ENV_CONSTANTS } from '@firebase/util';
 import { PersistentStorage } from '../core/storage/storage';
 import { jsonEval, stringify } from '@firebase/util';
 import { isNodeSdk } from '@firebase/util';
 import { Transport } from './Transport';
 import { StatsCollection } from '../core/stats/StatsCollection';
+import { SDK_VERSION } from '../core/version';
 
 const WEBSOCKET_MAX_FRAME_SIZE = 16384;
 const WEBSOCKET_KEEPALIVE_INTERVAL = 45000;
@@ -151,7 +150,7 @@ export class WebSocketConnection implements Transport {
         const options: { [k: string]: object } = {
           headers: {
             'User-Agent': `Firebase/${PROTOCOL_VERSION}/${
-              firebase.SDK_VERSION
+              SDK_VERSION
             }/${process.platform}/${device}`
           }
         };

From 9088571fdc7d48f15064e459fefda50b7ef98ba4 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 14:43:10 -0700
Subject: [PATCH 02/11] some comment

---
 packages/database/src/core/version.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/database/src/core/version.ts b/packages/database/src/core/version.ts
index f63e9b8619a..c5e51fc4248 100644
--- a/packages/database/src/core/version.ts
+++ b/packages/database/src/core/version.ts
@@ -2,6 +2,7 @@
 /** The semver (www.semver.org) version of the SDK. */
 export let SDK_VERSION = '';
 
+// SDK_VERSION should be set before any database instance is created
 export function setSDKVersion(version: string): void {
     SDK_VERSION = version;
 }

From 282b9163b1c0bff29bc633f3864af9e971301a00 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 15:30:58 -0700
Subject: [PATCH 03/11] remove the unnecessary build target

---
 packages/app/src/firebaseNamespaceCore.ts |  8 ----
 packages/database/index.admin.ts          | 50 -----------------------
 packages/database/index.node.ts           | 49 +++++++++++++++++++---
 packages/database/index.ts                |  2 +-
 packages/database/rollup.config.js        |  9 ----
 5 files changed, 45 insertions(+), 73 deletions(-)
 delete mode 100644 packages/database/index.admin.ts

diff --git a/packages/app/src/firebaseNamespaceCore.ts b/packages/app/src/firebaseNamespaceCore.ts
index a269406b556..eefbc91607e 100644
--- a/packages/app/src/firebaseNamespaceCore.ts
+++ b/packages/app/src/firebaseNamespaceCore.ts
@@ -70,14 +70,6 @@ export function createFirebaseNamespaceCore(
     }
   };
 
-  // setting version on CONSTANTS, so @firebase/database can get the version from 
-  // @firebase/util instead of @firebase/app. So we can provide a special build target
-  // for @firebase/database that has no dependency on @firebase/app. The special build target will
-  // be used by firebase-admin. It is to solve a version conflict (@firebase/app) that could happen 
-  // when firebase and firebase-admin are used in the same project.
-  // https://github.com/firebase/firebase-js-sdk/issues/1696#issuecomment-501546596
-  CONSTANTS.SDK_VERSION = version;
-
   // Inject a circular default export to allow Babel users who were previously
   // using:
   //
diff --git a/packages/database/index.admin.ts b/packages/database/index.admin.ts
deleted file mode 100644
index 5af339b488f..00000000000
--- a/packages/database/index.admin.ts
+++ /dev/null
@@ -1,50 +0,0 @@
-import { CONSTANTS } from '@firebase/util';
-import { FirebaseApp } from '@firebase/app-types';
-import { _FirebaseNamespace } from '@firebase/app-types/private';
-import { Database } from './src/api/Database';
-import { DataSnapshot } from './src/api/DataSnapshot';
-import { Query } from './src/api/Query';
-import { Reference } from './src/api/Reference';
-import { enableLogging } from './src/core/util/util';
-import { RepoManager } from './src/core/RepoManager';
-import * as INTERNAL from './src/api/internal';
-import * as TEST_ACCESS from './src/api/test_access';
-import './src/nodePatches';
-import { setSDKVersion } from './src/core/version';
-
-/**
- * A one off register function which returns a database based on the app and
- * passed database URL.
- *
- * @param app A valid FirebaseApp-like object
- * @param url A valid Firebase databaseURL
- */
-
-const ServerValue = Database.ServerValue;
-
-export function initStandalone(
-  app: FirebaseApp,
-  url: string,
-  version: string
-) {
-  /**
-   * This should allow the firebase-admin package to provide a custom version
-   * to the backend
-   */
-  CONSTANTS.NODE_ADMIN = true;
-  setSDKVersion(version);
-
-  return {
-    instance: RepoManager.getInstance().databaseFromApp(app, url),
-    namespace: {
-      Reference,
-      Query,
-      Database,
-      DataSnapshot,
-      enableLogging,
-      INTERNAL,
-      ServerValue,
-      TEST_ACCESS
-    }
-  };
-}
\ No newline at end of file
diff --git a/packages/database/index.node.ts b/packages/database/index.node.ts
index 55cf64c08b0..da0811d49b7 100644
--- a/packages/database/index.node.ts
+++ b/packages/database/index.node.ts
@@ -15,8 +15,7 @@
  * limitations under the License.
  */
 
-import firebase from '@firebase/app';
-import { FirebaseNamespace } from '@firebase/app-types';
+import { FirebaseNamespace, FirebaseApp } from '@firebase/app-types';
 import { _FirebaseNamespace } from '@firebase/app-types/private';
 import { Database } from './src/api/Database';
 import { DataSnapshot } from './src/api/DataSnapshot';
@@ -29,6 +28,10 @@ import * as TEST_ACCESS from './src/api/test_access';
 import './src/nodePatches';
 import * as types from '@firebase/database-types';
 import { setSDKVersion } from './src/core/version';
+import { CONSTANTS } from '@firebase/util';
+
+
+const ServerValue = Database.ServerValue;
 
 /**
  * A one off register function which returns a database based on the app and
@@ -36,14 +39,39 @@ import { setSDKVersion } from './src/core/version';
  *
  * @param app A valid FirebaseApp-like object
  * @param url A valid Firebase databaseURL
+ * @param version custom version e.g. firebase-admin version
  */
+export function initStandalone(
+  app: FirebaseApp,
+  url: string,
+  version: string
+) {
+  /**
+   * This should allow the firebase-admin package to provide a custom version
+   * to the backend
+   */
+  CONSTANTS.NODE_ADMIN = true;
+  setSDKVersion(version);
 
-const ServerValue = Database.ServerValue;
+  return {
+    instance: RepoManager.getInstance().databaseFromApp(app, url),
+    namespace: {
+      Reference,
+      Query,
+      Database,
+      DataSnapshot,
+      enableLogging,
+      INTERNAL,
+      ServerValue,
+      TEST_ACCESS
+    }
+  };
+}
 
 export function registerDatabase(instance: FirebaseNamespace) {
   
   // set SDK_VERSION
-  setSDKVersion(firebase.SDK_VERSION);
+  setSDKVersion(instance.SDK_VERSION);
 
   // Register the Database Service with the 'firebase' namespace.
   (instance as _FirebaseNamespace).INTERNAL.registerService(
@@ -65,7 +93,18 @@ export function registerDatabase(instance: FirebaseNamespace) {
   );
 }
 
-registerDatabase(firebase);
+try {
+  // If @firebase/app is not present, skip registering database.
+  // It could happen when this package is used in firebase-admin which doesn't depend on @firebase/app.
+  // Previously firebase-admin depends on @firebase/app, which causes version conflict on 
+  // @firebase/app when used together with the js sdk. More detail:
+  // https://github.com/firebase/firebase-js-sdk/issues/1696#issuecomment-501546596
+  const firebase = require('@firebase/app');
+  registerDatabase(firebase);
+} catch(err) {
+
+}
+
 
 // Types to export for the admin SDK
 export { Database, Query, Reference, enableLogging, ServerValue };
diff --git a/packages/database/index.ts b/packages/database/index.ts
index 5de3b8bb385..76e3e55a647 100644
--- a/packages/database/index.ts
+++ b/packages/database/index.ts
@@ -35,7 +35,7 @@ const ServerValue = Database.ServerValue;
 export function registerDatabase(instance: FirebaseNamespace) {
   
   // set SDK_VERSION
-  setSDKVersion(firebase.SDK_VERSION);
+  setSDKVersion(instance.SDK_VERSION);
   
   // Register the Database Service with the 'firebase' namespace.
   const namespace = (instance as _FirebaseNamespace).INTERNAL.registerService(
diff --git a/packages/database/rollup.config.js b/packages/database/rollup.config.js
index 20c09dfecf4..365301f11e9 100644
--- a/packages/database/rollup.config.js
+++ b/packages/database/rollup.config.js
@@ -42,15 +42,6 @@ const es5Builds = [
     plugins: es5BuildPlugins,
     external: id => deps.some(dep => id === dep || id.startsWith(`${dep}/`))
   },
-  /**
-   * Node.js Build for firebase-admin (no dep on @firebase/app)
-   */
-  {
-    input: 'index.admin.ts',
-    output: [{ file: pkg['main-admin'], format: 'cjs', sourcemap: true }],
-    plugins: es5BuildPlugins,
-    external: id => deps.some(dep => id === dep || id.startsWith(`${dep}/`))
-  },
   /**
    * Browser Builds
    */

From 174346767614d6964b3ea362f9f87dcc57e245c6 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 16:35:06 -0700
Subject: [PATCH 04/11] require default

---
 packages/database/index.node.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/database/index.node.ts b/packages/database/index.node.ts
index da0811d49b7..d95826c536a 100644
--- a/packages/database/index.node.ts
+++ b/packages/database/index.node.ts
@@ -99,10 +99,11 @@ try {
   // Previously firebase-admin depends on @firebase/app, which causes version conflict on 
   // @firebase/app when used together with the js sdk. More detail:
   // https://github.com/firebase/firebase-js-sdk/issues/1696#issuecomment-501546596
-  const firebase = require('@firebase/app');
+  const firebase = require('@firebase/app').default;
   registerDatabase(firebase);
 } catch(err) {
-
+  // catch 'MODULE_NOT_FOUND' error in firebase-admin
+  // we can safely ignore this error because RTDB in firebase-admin works without @firebase/app
 }
 
 

From 5ef2697d71daf2a3b850324e1adce4e9bb444442 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 16:35:25 -0700
Subject: [PATCH 05/11] [AUTOMATED]: Prettier Code Styling

---
 packages/database/index.node.ts                     | 13 +++----------
 packages/database/index.ts                          |  3 +--
 packages/database/src/core/PersistentConnection.ts  | 11 +++++++----
 packages/database/src/core/version.ts               |  3 +--
 .../database/src/realtime/WebSocketConnection.ts    |  6 +++---
 5 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/packages/database/index.node.ts b/packages/database/index.node.ts
index d95826c536a..2050fa03b7a 100644
--- a/packages/database/index.node.ts
+++ b/packages/database/index.node.ts
@@ -30,7 +30,6 @@ import * as types from '@firebase/database-types';
 import { setSDKVersion } from './src/core/version';
 import { CONSTANTS } from '@firebase/util';
 
-
 const ServerValue = Database.ServerValue;
 
 /**
@@ -41,11 +40,7 @@ const ServerValue = Database.ServerValue;
  * @param url A valid Firebase databaseURL
  * @param version custom version e.g. firebase-admin version
  */
-export function initStandalone(
-  app: FirebaseApp,
-  url: string,
-  version: string
-) {
+export function initStandalone(app: FirebaseApp, url: string, version: string) {
   /**
    * This should allow the firebase-admin package to provide a custom version
    * to the backend
@@ -69,7 +64,6 @@ export function initStandalone(
 }
 
 export function registerDatabase(instance: FirebaseNamespace) {
-  
   // set SDK_VERSION
   setSDKVersion(instance.SDK_VERSION);
 
@@ -96,17 +90,16 @@ export function registerDatabase(instance: FirebaseNamespace) {
 try {
   // If @firebase/app is not present, skip registering database.
   // It could happen when this package is used in firebase-admin which doesn't depend on @firebase/app.
-  // Previously firebase-admin depends on @firebase/app, which causes version conflict on 
+  // Previously firebase-admin depends on @firebase/app, which causes version conflict on
   // @firebase/app when used together with the js sdk. More detail:
   // https://github.com/firebase/firebase-js-sdk/issues/1696#issuecomment-501546596
   const firebase = require('@firebase/app').default;
   registerDatabase(firebase);
-} catch(err) {
+} catch (err) {
   // catch 'MODULE_NOT_FOUND' error in firebase-admin
   // we can safely ignore this error because RTDB in firebase-admin works without @firebase/app
 }
 
-
 // Types to export for the admin SDK
 export { Database, Query, Reference, enableLogging, ServerValue };
 
diff --git a/packages/database/index.ts b/packages/database/index.ts
index 76e3e55a647..00a3848447c 100644
--- a/packages/database/index.ts
+++ b/packages/database/index.ts
@@ -33,10 +33,9 @@ import { setSDKVersion } from './src/core/version';
 const ServerValue = Database.ServerValue;
 
 export function registerDatabase(instance: FirebaseNamespace) {
-  
   // set SDK_VERSION
   setSDKVersion(instance.SDK_VERSION);
-  
+
   // Register the Database Service with the 'firebase' namespace.
   const namespace = (instance as _FirebaseNamespace).INTERNAL.registerService(
     'database',
diff --git a/packages/database/src/core/PersistentConnection.ts b/packages/database/src/core/PersistentConnection.ts
index 0c247cecf57..b9c1ca7a76a 100644
--- a/packages/database/src/core/PersistentConnection.ts
+++ b/packages/database/src/core/PersistentConnection.ts
@@ -15,7 +15,12 @@
  * limitations under the License.
  */
 
-import { contains, isEmpty, safeGet, CONSTANTS } from '@firebase/util';
+import {
+  contains,
+  isEmpty,
+  safeGet,
+  CONSTANTS
+} from '@firebase/util';
 import { stringify } from '@firebase/util';
 import { assert } from '@firebase/util';
 import { error, log, logWrapper, warn, ObjectToUniqueKey } from './util/util';
@@ -925,9 +930,7 @@ export class PersistentConnection extends ServerActions {
       clientName = 'node';
     }
 
-    stats[
-      'sdk.' + clientName + '.' + SDK_VERSION.replace(/\./g, '-')
-    ] = 1;
+    stats['sdk.' + clientName + '.' + SDK_VERSION.replace(/\./g, '-')] = 1;
 
     if (isMobileCordova()) {
       stats['framework.cordova'] = 1;
diff --git a/packages/database/src/core/version.ts b/packages/database/src/core/version.ts
index c5e51fc4248..026d142a2a9 100644
--- a/packages/database/src/core/version.ts
+++ b/packages/database/src/core/version.ts
@@ -1,8 +1,7 @@
-
 /** The semver (www.semver.org) version of the SDK. */
 export let SDK_VERSION = '';
 
 // SDK_VERSION should be set before any database instance is created
 export function setSDKVersion(version: string): void {
-    SDK_VERSION = version;
+  SDK_VERSION = version;
 }
diff --git a/packages/database/src/realtime/WebSocketConnection.ts b/packages/database/src/realtime/WebSocketConnection.ts
index e6dcc0c5c62..4601e9b4a76 100644
--- a/packages/database/src/realtime/WebSocketConnection.ts
+++ b/packages/database/src/realtime/WebSocketConnection.ts
@@ -149,9 +149,9 @@ export class WebSocketConnection implements Transport {
         // UA Format: Firebase/<wire_protocol>/<sdk_version>/<platform>/<device>
         const options: { [k: string]: object } = {
           headers: {
-            'User-Agent': `Firebase/${PROTOCOL_VERSION}/${
-              SDK_VERSION
-            }/${process.platform}/${device}`
+            'User-Agent': `Firebase/${PROTOCOL_VERSION}/${SDK_VERSION}/${
+              process.platform
+            }/${device}`
           }
         };
 

From 35efa6dcef93800ea09a7cb2ac10644c5859697e Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 16:35:27 -0700
Subject: [PATCH 06/11] [AUTOMATED]: License Headers

---
 packages/database/src/core/version.ts | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/packages/database/src/core/version.ts b/packages/database/src/core/version.ts
index 026d142a2a9..cbdb1b09894 100644
--- a/packages/database/src/core/version.ts
+++ b/packages/database/src/core/version.ts
@@ -1,3 +1,20 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 /** The semver (www.semver.org) version of the SDK. */
 export let SDK_VERSION = '';
 

From da4717cbb01be2bb793ae484f6baefe088a85292 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 16:40:46 -0700
Subject: [PATCH 07/11] remove experimental changes

---
 packages/database/package.json | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/database/package.json b/packages/database/package.json
index fe04070a22c..6b88211f952 100644
--- a/packages/database/package.json
+++ b/packages/database/package.json
@@ -7,7 +7,6 @@
   "browser": "dist/index.cjs.js",
   "module": "dist/index.esm.js",
   "esm2017": "dist/index.esm2017.js",
-  "main-admin": "dist/index.admin.node.cjs.js",
   "files": [
     "dist"
   ],

From 092c99ca915fb6e108dd5bb7cbf19cd4387eebd5 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Tue, 25 Jun 2019 17:00:56 -0700
Subject: [PATCH 08/11] remove unused var

---
 packages/app/src/firebaseNamespaceCore.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/app/src/firebaseNamespaceCore.ts b/packages/app/src/firebaseNamespaceCore.ts
index eefbc91607e..4b6dcdcc9fe 100644
--- a/packages/app/src/firebaseNamespaceCore.ts
+++ b/packages/app/src/firebaseNamespaceCore.ts
@@ -29,7 +29,7 @@ import {
   FirebaseServiceNamespace,
   AppHook
 } from '@firebase/app-types/private';
-import { deepExtend, contains, CONSTANTS } from '@firebase/util';
+import { deepExtend, contains } from '@firebase/util';
 import { FirebaseAppImpl } from './firebaseApp';
 import { ERROR_FACTORY, AppError } from './errors';
 import { FirebaseAppLiteImpl } from './lite/firebaseAppLite';

From e794be100ef503855394d32760047c5b4b258509 Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Wed, 26 Jun 2019 15:07:43 -0700
Subject: [PATCH 09/11] only ignore MODULE_NOT_FOUND error

---
 packages/database/index.node.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/database/index.node.ts b/packages/database/index.node.ts
index 2050fa03b7a..10e307a95a8 100644
--- a/packages/database/index.node.ts
+++ b/packages/database/index.node.ts
@@ -96,8 +96,11 @@ try {
   const firebase = require('@firebase/app').default;
   registerDatabase(firebase);
 } catch (err) {
-  // catch 'MODULE_NOT_FOUND' error in firebase-admin
+  // catch and ignore 'MODULE_NOT_FOUND' error in firebase-admin context
   // we can safely ignore this error because RTDB in firebase-admin works without @firebase/app
+  if (err.code !== 'MODULE_NOT_FOUND') {
+    throw err;
+  }
 }
 
 // Types to export for the admin SDK

From c47ea2ba4fd829b1e5f2183d242adff8c51b48df Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Fri, 28 Jun 2019 16:41:41 -0700
Subject: [PATCH 10/11] [AUTOMATED]: Prettier Code Styling

---
 packages/database/src/core/PersistentConnection.ts | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/packages/database/src/core/PersistentConnection.ts b/packages/database/src/core/PersistentConnection.ts
index b9c1ca7a76a..08f9261f8d4 100644
--- a/packages/database/src/core/PersistentConnection.ts
+++ b/packages/database/src/core/PersistentConnection.ts
@@ -15,12 +15,7 @@
  * limitations under the License.
  */
 
-import {
-  contains,
-  isEmpty,
-  safeGet,
-  CONSTANTS
-} from '@firebase/util';
+import { contains, isEmpty, safeGet, CONSTANTS } from '@firebase/util';
 import { stringify } from '@firebase/util';
 import { assert } from '@firebase/util';
 import { error, log, logWrapper, warn, ObjectToUniqueKey } from './util/util';

From 05f667fd9f214b46a5911a57c886a890440c27ca Mon Sep 17 00:00:00 2001
From: Feiyang1 <plane1113@gmail.com>
Date: Mon, 1 Jul 2019 09:56:23 -0700
Subject: [PATCH 11/11] revert module export change

---
 packages/database/index.node.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/database/index.node.ts b/packages/database/index.node.ts
index 10e307a95a8..a58988c507f 100644
--- a/packages/database/index.node.ts
+++ b/packages/database/index.node.ts
@@ -28,7 +28,7 @@ import * as TEST_ACCESS from './src/api/test_access';
 import './src/nodePatches';
 import * as types from '@firebase/database-types';
 import { setSDKVersion } from './src/core/version';
-import { CONSTANTS } from '@firebase/util';
+import { CONSTANTS, isNodeSdk } from '@firebase/util';
 
 const ServerValue = Database.ServerValue;
 
@@ -68,7 +68,7 @@ export function registerDatabase(instance: FirebaseNamespace) {
   setSDKVersion(instance.SDK_VERSION);
 
   // Register the Database Service with the 'firebase' namespace.
-  (instance as _FirebaseNamespace).INTERNAL.registerService(
+  const namespace = (instance as _FirebaseNamespace).INTERNAL.registerService(
     'database',
     (app, unused, url) => RepoManager.getInstance().databaseFromApp(app, url),
     // firebase.database namespace properties
@@ -85,6 +85,10 @@ export function registerDatabase(instance: FirebaseNamespace) {
     null,
     true
   );
+
+  if (isNodeSdk()) {
+    module.exports = Object.assign({}, namespace, { initStandalone });
+  }
 }
 
 try {