From 9e05bafe2f221fdf78b3e591b96c75ffddc04e5a Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Sat, 25 Jun 2022 21:49:03 -0400
Subject: [PATCH] perf(document+internal): put default value for `$isNew` and
 `strictMode` on prototype to avoid unnecessary memory usage

Re: #11541
---
 lib/document.js | 19 ++++++++++++++++---
 lib/internal.js |  3 ++-
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/lib/document.js b/lib/document.js
index b74b04988a6..d30e789a099 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -93,7 +93,11 @@ function Document(obj, fields, skipId, options) {
   }
 
   this.$__ = new InternalCache();
-  this.$isNew = 'isNew' in options ? options.isNew : true;
+
+  // Avoid setting `isNew` to `true`, because it is `true` by default
+  if (options.isNew != null && options.isNew !== true) {
+    this.$isNew = options.isNew;
+  }
 
   if (options.priorDoc != null) {
     this.$__.priorDoc = options.priorDoc;
@@ -116,9 +120,11 @@ function Document(obj, fields, skipId, options) {
   const schema = this.$__schema;
 
   if (typeof fields === 'boolean' || fields === 'throw') {
-    this.$__.strictMode = fields;
+    if (fields !== true) {
+      this.$__.strictMode = fields;
+    }
     fields = undefined;
-  } else {
+  } else if (schema.options.strict !== true) {
     this.$__.strictMode = schema.options.strict;
   }
 
@@ -207,6 +213,13 @@ Object.defineProperty(Document.prototype, 'errors', {
     this.$errors = value;
   }
 });
+
+/*!
+ * ignore
+ */
+
+Document.prototype.$isNew = true;
+
 /*!
  * Document exposes the NodeJS event emitter API, so you can use
  * `on`, `once`, etc.
diff --git a/lib/internal.js b/lib/internal.js
index a31714825f9..d7fe08d5b87 100644
--- a/lib/internal.js
+++ b/lib/internal.js
@@ -13,8 +13,9 @@ function InternalCache() {
   this.activePaths = new ActiveRoster();
 }
 
+InternalCache.prototype.strictMode = true;
+
 InternalCache.prototype.fullPath = undefined;
-InternalCache.prototype.strictMode = undefined;
 InternalCache.prototype.selected = undefined;
 InternalCache.prototype.shardval = undefined;
 InternalCache.prototype.saveError = undefined;