More toObject() perf improvements

lib/document.js

@@ -3798,11 +3798,6 @@ Document.prototype.$__handleReject = function handleReject(err) {
  */
 
 Document.prototype.$toObject = function(options, json) {
-  const defaultOptions = {
-    transform: true,
-    flattenDecimals: true
-  };
-
   const path = json ? 'toJSON' : 'toObject';
   const baseOptions = this.constructor &&
     this.constructor.base &&
@@ -3811,7 +3806,7 @@ Document.prototype.$toObject = function(options, json) {
   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.
-  Object.assign(defaultOptions, baseOptions, schemaOptions[path]);
+  const defaultOptions = Object.assign({}, baseOptions, schemaOptions[path]);
 
   // If options do not exist or is not an object, set it to empty object
   options = utils.isPOJO(options) ? { ...options } : {};
@@ -3826,45 +3821,17 @@ Document.prototype.$toObject = function(options, json) {
     _minimize = schemaOptions.minimize;
   }
 
-  let flattenMaps;
-  if (options._calledWithOptions.flattenMaps != null) {
-    flattenMaps = options.flattenMaps;
-  } else if (defaultOptions.flattenMaps != null) {
-    flattenMaps = defaultOptions.flattenMaps;
-  } else {
-    flattenMaps = schemaOptions.flattenMaps;
-  }
-
-  let flattenObjectIds;
-  if (options._calledWithOptions.flattenObjectIds != null) {
-    flattenObjectIds = options.flattenObjectIds;
-  } else if (defaultOptions.flattenObjectIds != null) {
-    flattenObjectIds = defaultOptions.flattenObjectIds;
-  } else {
-    flattenObjectIds = schemaOptions.flattenObjectIds;
-  }
-
-  // The original options that will be passed to `clone()`. Important because
-  // `clone()` will recursively call `$toObject()` on embedded docs, so we
-  // need the original options the user passed in, plus `_isNested` and
-  // `_parentOptions` for checking whether we need to depopulate.
-  const cloneOptions = {
-    ...options,
-    _isNested: true,
-    json: json,
-    minimize: _minimize,
-    flattenMaps: flattenMaps,
-    flattenObjectIds: flattenObjectIds,
-    _seen: (options && options._seen) || new Map(),
-    _calledWithOptions: options._calledWithOptions
-  };
+  options.minimize = _minimize;
+  options._seen = options._seen || new Map();
 
-  const depopulate = options.depopulate ||
-    (options._parentOptions && options._parentOptions.depopulate || false);
+  const depopulate = options._calledWithOptions.depopulate
+    ?? options._parentOptions?.depopulate
+    ?? defaultOptions.depopulate
+    ?? false;
   // _isNested will only be true if this is not the top level document, we
   // should never depopulate the top-level document
   if (depopulate && options._isNested && this.$__.wasPopulated) {
-    return clone(this.$__.wasPopulated.value || this._id, cloneOptions);
+    return clone(this.$__.wasPopulated.value || this._id, options);
   }
 
   // merge default options with input options.
@@ -3877,33 +3844,47 @@ Document.prototype.$toObject = function(options, json) {
   options.json = json;
   options.minimize = _minimize;
 
-  cloneOptions._parentOptions = options;
+  options._parentOptions = options;
 
-  cloneOptions._skipSingleNestedGetters = false;
+  options._skipSingleNestedGetters = false;
   // remember the root transform function
   // to save it from being overwritten by sub-transform functions
-  const originalTransform = options.transform;
+  // const originalTransform = options.transform;
 
-  let ret = clone(this._doc, cloneOptions) || {};
+  let ret = clone(this._doc, options) || {};
 
-  cloneOptions._skipSingleNestedGetters = true;
-  if (options.getters) {
-    applyGetters(this, ret, cloneOptions);
+  options._skipSingleNestedGetters = true;
+  const getters = options._calledWithOptions.getters
+    ?? options.getters
+    ?? defaultOptions.getters
+    ?? false;
+  if (getters) {
+    applyGetters(this, ret, options);
 
     if (options.minimize) {
       ret = minimize(ret) || {};
     }
   }
 
-  if (options.virtuals || (options.getters && options.virtuals !== false)) {
-    applyVirtuals(this, ret, cloneOptions, options);
+  const virtuals = options._calledWithOptions.virtuals
+    ?? defaultOptions.virtuals
+    ?? undefined;
+
+  if (virtuals || (getters && virtuals !== false)) {
+    applyVirtuals(this, ret, options, options);
   }
 
   if (options.versionKey === false && this.$__schema.options.versionKey) {
     delete ret[this.$__schema.options.versionKey];
   }
 
-  let transform = options.transform;
+  const transform = options._calledWithOptions.transform ?? true;
+  let transformFunction = undefined;
+  if (transform === true) {
+    transformFunction = defaultOptions.transform;
+  } else if (typeof transform === 'function') {
+    transformFunction = transform;
+  }
 
   // In the case where a subdocument has its own transform function, we need to
   // check and see if the parent has a transform (options.transform) and if the
@@ -3918,18 +3899,8 @@ Document.prototype.$toObject = function(options, json) {
     omitDeselectedFields(this, ret);
   }
 
-  if (transform === true || (schemaOptions.toObject && transform)) {
-    const opts = options.json ? schemaOptions.toJSON : schemaOptions.toObject;
-
-    if (opts) {
-      transform = (typeof options.transform === 'function' ? options.transform : opts.transform);
-    }
-  } else {
-    options.transform = originalTransform;
-  }
-
-  if (typeof transform === 'function') {
-    const xformed = transform(this, ret, options);
+  if (typeof transformFunction === 'function') {
+    const xformed = transformFunction(this, ret, options);
     if (typeof xformed !== 'undefined') {
       ret = xformed;
     }
@@ -4146,7 +4117,8 @@ function applyVirtuals(self, json, options, toObjectOptions) {
       assignPath = path.substring(options.path.length + 1);
     }
     if (assignPath.indexOf('.') === -1 && assignPath === path) {
-      v = clone(self.get(path, { noDottedPath: true }), options);
+      v = self.get(path, null, { noDottedPath: true });
+      v = clone(v, options);
       if (v === void 0) {
         continue;
       }

lib/helpers/clone.js

@@ -40,7 +40,7 @@ function clone(obj, options, isArrayChild) {
       // Single nested subdocs should apply getters later in `applyGetters()`
       // when calling `toObject()`. See gh-7442, gh-8295
       if (options._skipSingleNestedGetters && obj.$isSingleNested) {
-        options = Object.assign({}, options, { getters: false });
+        options._calledWithOptions = Object.assign({}, options._calledWithOptions || {}, { getters: false });
       }
       if (options.retainDocuments && obj.$__ != null) {
         const clonedDoc = obj.$clone();

test/document.test.js

@@ -711,18 +711,19 @@ describe('document', function() {
         name: String,
         email: String
       });
-      const topicSchema = new Schema({
-        title: String,
-        email: String,
-        followers: [userSchema]
-      });
 
       userSchema.options.toObject = {
         transform: function(doc, ret) {
           delete ret.email;
         }
       };
 
+      const topicSchema = new Schema({
+        title: String,
+        email: String,
+        followers: [userSchema]
+      });
+
       topicSchema.options.toObject = {
         transform: function(doc, ret) {
           ret.title = ret.title.toLowerCase();
@@ -833,7 +834,10 @@ describe('document', function() {
       const userSchema = Schema({
         firstName: String,
         company: {
-          type: { companyId: { type: Schema.Types.ObjectId }, companyName: String }
+          type: {
+            companyId: { type: Schema.Types.ObjectId },
+            companyName: String
+          }
         }
       }, {
         toObject: {
@@ -849,6 +853,7 @@ describe('document', function() {
 
       const User = db.model('User', userSchema);
       const user = new User({ firstName: 'test', company: { companyName: 'foo' } });
+      assert.equal(transformCalls.length, 0);
       const obj = user.toObject();
       assert.strictEqual(obj.company.details, 42);
       assert.equal(transformCalls.length, 1);
@@ -1045,7 +1050,10 @@ describe('document', function() {
       const userSchema = Schema({
         firstName: String,
         company: {
-          type: { companyId: { type: Schema.Types.ObjectId }, companyName: String }
+          type: {
+            companyId: { type: Schema.Types.ObjectId },
+            companyName: String
+          }
         }
       }, {
         id: false,

test/helpers/clone.test.js

@@ -88,7 +88,7 @@ describe('clone', () => {
         $isSingleNested: true,
         toObject(cloneOpts) {
           assert.deepStrictEqual(
-            Object.assign({}, baseOpts, { getters: false }),
+            Object.assign({}, baseOpts),
             cloneOpts
           );
           const obj = JSON.parse(JSON.stringify(base));