perf: memoize default toObject options on a per-schema basis re: #14394

Author: vkarpov15

lib/document.js

@@ -22,7 +22,6 @@ const clone = require('./helpers/clone');
 const compile = require('./helpers/document/compile').compile;
 const defineKey = require('./helpers/document/compile').defineKey;
 const flatten = require('./helpers/common').flatten;
-const get = require('./helpers/get');
 const getEmbeddedDiscriminatorPath = require('./helpers/document/getEmbeddedDiscriminatorPath');
 const getKeysInSchemaOrder = require('./helpers/schema/getKeysInSchemaOrder');
 const getSubdocumentStrictValue = require('./helpers/schema/getSubdocumentStrictValue');
@@ -3798,15 +3797,7 @@ Document.prototype.$__handleReject = function handleReject(err) {
  */
 
 Document.prototype.$toObject = function(options, json) {
-  const path = json ? 'toJSON' : 'toObject';
-  const baseOptions = this.constructor &&
-    this.constructor.base &&
-    this.constructor.base.options &&
-    get(this.constructor.base.options, path) || {};
-  const schemaOptions = this.$__schema && this.$__schema.options || {};
-  // merge base default options with Schema's set default options if available.
-  // `clone` is necessary here because `utils.options` directly modifies the second input.
-  const defaultOptions = Object.assign({}, baseOptions, schemaOptions[path]);
+  const defaultOptions = this.$__schema._getDefaultToObjectOptions();
 
   // If options do not exist or is not an object, set it to empty object
   options = utils.isPOJO(options) ? { ...options } : {};
@@ -3815,10 +3806,8 @@ Document.prototype.$toObject = function(options, json) {
   let _minimize;
   if (options._calledWithOptions.minimize != null) {
     _minimize = options.minimize;
-  } else if (defaultOptions.minimize != null) {
-    _minimize = defaultOptions.minimize;
   } else {
-    _minimize = schemaOptions.minimize;
+    _minimize = defaultOptions.minimize;
   }
 
   options.minimize = _minimize;
@@ -3842,14 +3831,8 @@ Document.prototype.$toObject = function(options, json) {
   }
   options._isNested = true;
   options.json = json;
-  options.minimize = _minimize;
-
   options._parentOptions = options;
-
   options._skipSingleNestedGetters = false;
-  // remember the root transform function
-  // to save it from being overwritten by sub-transform functions
-  // const originalTransform = options.transform;
 
   let ret = clone(this._doc, options) || {};
 

lib/schema.js

@@ -128,6 +128,7 @@ function Schema(obj, options) {
   // For internal debugging. Do not use this to try to save a schema in MDB.
   this.$id = ++id;
   this.mapPaths = [];
+  this._defaultToObjectOptions = null;
 
   this.s = {
     hooks: new Kareem()
@@ -2597,6 +2598,33 @@ Schema.prototype.loadClass = function(model, virtualsOnly) {
   return this;
 };
 
+/**
+ * Returns default `toObject` / `toJSON` options for this schema,
+ * combining the associated
+ *
+ * @param {Boolean} json
+ * @returns object
+ */
+
+Schema.prototype._getDefaultToObjectOptions = function _getDefaultToObjectOptions(json) {
+  const path = json ? 'toJSON' : 'toObject';
+
+  if (this._defaultToObjectOptions && this._defaultToObjectOptions[path]) {
+    return this._defaultToObjectOptions[path];
+  }
+
+  const baseOptions = this.base && this.base.options && this.base.options[path];
+  const schemaOptions = this.options && this.options[path];
+  const defaultOptions = Object.assign(
+    {},
+    baseOptions,
+    schemaOptions
+  );
+  this._defaultToObjectOptions = this._defaultToObjectOptions || {};
+  this._defaultToObjectOptions[path] = defaultOptions;
+  return defaultOptions;
+};
+
 /*!
  * ignore
  */