From 6e5176aa8073bdc82c8dc1653b358537dee72410 Mon Sep 17 00:00:00 2001
From: Luca Pizzini <lpizzini7@gmail.com>
Date: Sat, 11 Feb 2023 11:47:56 +0100
Subject: [PATCH 1/2] feat(index): added createInitialConnection option to
 Mongoose constructor

closes #12965
---
 lib/index.js               | 7 +++++--
 test/connection.test.js    | 7 +++++++
 types/mongooseoptions.d.ts | 7 +++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/index.js b/lib/index.js
index 75051293bce..7060797440a 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -71,8 +71,11 @@ function Mongoose(options) {
     autoIndex: true,
     autoCreate: true
   }, options);
-  const conn = this.createConnection(); // default connection
-  conn.models = this.models;
+  const createInitialConnection = utils.getOption('createInitialConnection', this.options) ?? true;
+  if (createInitialConnection) {
+    const conn = this.createConnection(); // default connection
+    conn.models = this.models;
+  }
 
   if (this.options.pluralization) {
     this._pluralize = legacyPluralize;
diff --git a/test/connection.test.js b/test/connection.test.js
index d27c7879605..bf8d06089a5 100644
--- a/test/connection.test.js
+++ b/test/connection.test.js
@@ -1526,4 +1526,11 @@ describe('connections:', function() {
     const connectionIds = m.connections.map(c => c.id);
     assert.deepEqual(connectionIds, [1, 2, 3, 4, 5]);
   });
+
+  it('should not create default connection with createInitialConnection = false (gh-12965)', function() {
+    const m = new mongoose.Mongoose({
+      createInitialConnection: false
+    });
+    assert.deepEqual(m.connections.length, 0);
+  });
 });
diff --git a/types/mongooseoptions.d.ts b/types/mongooseoptions.d.ts
index 2a42540670c..054f85e7606 100644
--- a/types/mongooseoptions.d.ts
+++ b/types/mongooseoptions.d.ts
@@ -63,6 +63,13 @@ declare module 'mongoose' {
      */
     cloneSchemas?: boolean;
 
+    /**
+     * Set to `false` to disable the creation of the initial default connection.
+     *
+     * @default true
+     */
+    createInitialConnection?: boolean;
+
     /**
      * If `true`, prints the operations mongoose sends to MongoDB to the console.
      * If a writable stream is passed, it will log to that stream, without colorization.

From 92f5924eab9c01e7dc248f201b3434d50155eefc Mon Sep 17 00:00:00 2001
From: Luca Pizzini <lpizzini7@gmail.com>
Date: Sat, 11 Feb 2023 11:56:57 +0100
Subject: [PATCH 2/2] fix: syntax error for node 12

---
 lib/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/index.js b/lib/index.js
index 7060797440a..d071cd9e4bb 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -71,8 +71,8 @@ function Mongoose(options) {
     autoIndex: true,
     autoCreate: true
   }, options);
-  const createInitialConnection = utils.getOption('createInitialConnection', this.options) ?? true;
-  if (createInitialConnection) {
+  const createInitialConnection = utils.getOption('createInitialConnection', this.options);
+  if (createInitialConnection == null || createInitialConnection) {
     const conn = this.createConnection(); // default connection
     conn.models = this.models;
   }