perf: optimize Object.keys() checks and optional chaining

lib/cast.js

@@ -79,7 +79,7 @@ module.exports = function cast(schema, obj, options, context) {
           val[k] = cast(discriminatorSchema ? discriminatorSchema : schema, val[k], options, context);
         }
 
-        if (Object.keys(val[k]).length === 0 && beforeCastKeysLength !== 0) {
+        if (utils.hasOwnKeys(val[k]) === false && beforeCastKeysLength !== 0) {
           val.splice(k, 1);
         }
       }
@@ -126,10 +126,7 @@ module.exports = function cast(schema, obj, options, context) {
           const pathFirstHalf = split.slice(0, j).join('.');
           const pathLastHalf = split.slice(j).join('.');
           const _schematype = schema.path(pathFirstHalf);
-          const discriminatorKey = _schematype &&
-            _schematype.schema &&
-            _schematype.schema.options &&
-            _schematype.schema.options.discriminatorKey;
+          const discriminatorKey = _schematype?.schema?.options?.discriminatorKey;
 
           // gh-6027: if we haven't found the schematype but this path is
           // underneath an embedded discriminator and the embedded discriminator
@@ -430,11 +427,7 @@ function getStrictQuery(queryOptions, schemaUserProvidedOptions, schemaOptions,
   if ('strictQuery' in schemaUserProvidedOptions) {
     return schemaUserProvidedOptions.strictQuery;
   }
-  const mongooseOptions = context &&
-    context.mongooseCollection &&
-    context.mongooseCollection.conn &&
-    context.mongooseCollection.conn.base &&
-    context.mongooseCollection.conn.base.options;
+  const mongooseOptions = context?.mongooseCollection?.conn?.base?.options;
   if (mongooseOptions) {
     if ('strictQuery' in mongooseOptions) {
       return mongooseOptions.strictQuery;

lib/connection.js

@@ -630,7 +630,7 @@ Connection.prototype.createCollections = async function createCollections(option
     }
   }
 
-  if (!continueOnError && Object.keys(errorsMap).length) {
+  if (!continueOnError && utils.hasOwnKeys(errorsMap)) {
     const message = Object.entries(errorsMap).map(([modelName, err]) => `${modelName}: ${err.message}`).join(', ');
     const createCollectionsError = new CreateCollectionsError(message, errorsMap);
     throw createCollectionsError;
@@ -1250,8 +1250,11 @@ Connection.prototype._close = async function _close(force, destroy) {
   const conn = this;
   switch (this.readyState) {
     case STATES.disconnected:
-      if (destroy && this.base.connections.indexOf(conn) !== -1) {
-        this.base.connections.splice(this.base.connections.indexOf(conn), 1);
+      if (destroy) {
+        const index = this.base.connections.indexOf(conn);
+        if (index !== -1) {
+          this.base.connections.splice(index, 1);
+        }
       }
       if (!closeCalled) {
         await this.doClose(force);
@@ -1262,8 +1265,11 @@ Connection.prototype._close = async function _close(force, destroy) {
     case STATES.connected:
       this.readyState = STATES.disconnecting;
       await this.doClose(force);
-      if (destroy && _this.base.connections.indexOf(conn) !== -1) {
-        this.base.connections.splice(this.base.connections.indexOf(conn), 1);
+      if (destroy) {
+        const index = _this.base.connections.indexOf(conn);
+        if (index !== -1) {
+          this.base.connections.splice(index, 1);
+        }
       }
       this.onClose(force);
 
@@ -1772,7 +1778,7 @@ Connection.prototype.syncIndexes = async function syncIndexes(options = {}) {
     }
   }
 
-  if (!continueOnError && Object.keys(errorsMap).length) {
+  if (!continueOnError && utils.hasOwnKeys(errorsMap)) {
     const message = Object.entries(errorsMap).map(([modelName, err]) => `${modelName}: ${err.message}`).join(', ');
     const syncIndexesError = new SyncIndexesError(message, errorsMap);
     throw syncIndexesError;

lib/cursor/changeStream.js

@@ -83,7 +83,7 @@ class ChangeStream extends EventEmitter {
 
           driverChangeStreamEvents.forEach(ev => {
             this.driverChangeStream.on(ev, data => {
-              if (data != null && data.fullDocument != null && this.options && this.options.hydrate) {
+              if (data?.fullDocument != null && this.options?.hydrate) {
                 data.fullDocument = this.options.model.hydrate(data.fullDocument);
               }
               this.emit(ev, data);
@@ -102,7 +102,7 @@ class ChangeStream extends EventEmitter {
 
     driverChangeStreamEvents.forEach(ev => {
       this.driverChangeStream.on(ev, data => {
-        if (data != null && data.fullDocument != null && this.options && this.options.hydrate) {
+        if (data?.fullDocument != null && this.options?.hydrate) {
           data.fullDocument = this.options.model.hydrate(data.fullDocument);
         }
         this.emit(ev, data);

lib/document.js

@@ -149,7 +149,7 @@ function Document(obj, fields, options) {
 
   // determine if this doc is a result of a query with
   // excluded fields
-  if (utils.isPOJO(fields) && Object.keys(fields).length > 0) {
+  if (utils.isPOJO(fields) && utils.hasOwnKeys(fields)) {
     exclude = isExclusive(fields);
     this.$__.selected = fields;
     this.$__.exclude = exclude;
@@ -1015,17 +1015,21 @@ Document.prototype.$timestamps = function $timestamps(value) {
  */
 
 Document.prototype.overwrite = function overwrite(obj) {
-  const keys = Array.from(new Set(Object.keys(this._doc).concat(Object.keys(obj))));
+  const keys = new Set(Object.keys(this._doc));
+  for (const key of Object.keys(obj)) {
+    keys.add(key);
+  }
 
+  const schemaOptions = this.$__schema.options;
   for (const key of keys) {
     if (key === '_id') {
       continue;
     }
     // Explicitly skip version key
-    if (this.$__schema.options.versionKey && key === this.$__schema.options.versionKey) {
+    if (schemaOptions.versionKey && key === schemaOptions.versionKey) {
       continue;
     }
-    if (this.$__schema.options.discriminatorKey && key === this.$__schema.options.discriminatorKey) {
+    if (schemaOptions.discriminatorKey && key === schemaOptions.discriminatorKey) {
       continue;
     }
     this.$set(key, obj[key]);
@@ -1697,7 +1701,7 @@ Document.prototype.$__set = function(pathToMark, path, options, constructing, pa
   if (shouldModify) {
     if (this.$__.primitiveAtomics && this.$__.primitiveAtomics[path]) {
       delete this.$__.primitiveAtomics[path];
-      if (Object.keys(this.$__.primitiveAtomics).length === 0) {
+      if (utils.hasOwnKeys(this.$__.primitiveAtomics) === false) {
         delete this.$__.primitiveAtomics;
       }
     }
@@ -3001,7 +3005,7 @@ Document.prototype.$__validate = async function $__validate(pathsToValidate, opt
           delete validationError.errors[errPath];
         }
       }
-      if (Object.keys(validationError.errors).length === 0) {
+      if (utils.hasOwnKeys(validationError.errors) === false) {
         validationError = void 0;
       }
     }
@@ -3402,7 +3406,7 @@ Document.prototype.$markValid = function(path) {
   }
 
   delete this.$__.validationError.errors[path];
-  if (Object.keys(this.$__.validationError.errors).length === 0) {
+  if (utils.hasOwnKeys(this.$__.validationError.errors) === false) {
     this.$__.validationError = null;
   }
 };
@@ -3422,7 +3426,7 @@ function _markValidSubpaths(doc, path) {
       delete doc.$__.validationError.errors[key];
     }
   }
-  if (Object.keys(doc.$__.validationError.errors).length === 0) {
+  if (utils.hasOwnKeys(doc.$__.validationError.errors) === false) {
     doc.$__.validationError = null;
   }
 }
@@ -3497,7 +3501,7 @@ function _checkImmutableSubpaths(subdoc, schematype, priorVal) {
  */
 
 Document.prototype.$isValid = function(path) {
-  if (this.$__.validationError == null || Object.keys(this.$__.validationError.errors).length === 0) {
+  if (this.$__.validationError == null || utils.hasOwnKeys(this.$__.validationError.errors) === false) {
     return true;
   }
   if (path == null) {
@@ -4375,7 +4379,7 @@ function omitDeselectedFields(self, json) {
     selected = {};
     queryhelpers.applyPaths(selected, schema);
   }
-  if (selected == null || Object.keys(selected).length === 0) {
+  if (selected == null || utils.hasOwnKeys(selected) === false) {
     return json;
   }
 
@@ -5057,7 +5061,7 @@ Document.prototype.$__delta = function $__delta() {
     this.$__version(where, delta);
   }
 
-  if (Object.keys(delta).length === 0) {
+  if (utils.hasOwnKeys(delta) === false) {
     return [where, null];
   }
 
@@ -5109,7 +5113,7 @@ function checkDivergentArray(doc, path, array) {
 
   if (check) {
     const atomics = array[arrayAtomicsSymbol];
-    if (Object.keys(atomics).length === 0 || atomics.$set || atomics.$pop) {
+    if (utils.hasOwnKeys(atomics) === false || atomics.$set || atomics.$pop) {
       return path;
     }
   }

lib/drivers/node-mongodb-native/collection.js

@@ -97,15 +97,8 @@ function iter(i) {
     const collection = this._getCollection();
     const args = Array.from(arguments);
     const _this = this;
-    const globalDebug = _this &&
-      _this.conn &&
-      _this.conn.base &&
-      _this.conn.base.options &&
-      _this.conn.base.options.debug;
-    const connectionDebug = _this &&
-      _this.conn &&
-      _this.conn.options &&
-      _this.conn.options.debug;
+    const globalDebug = _this?.conn?.base?.options?.debug;
+    const connectionDebug = _this?.conn?.options?.debug;
     const debug = connectionDebug == null ? globalDebug : connectionDebug;
     const lastArg = arguments[arguments.length - 1];
     const opId = new ObjectId();
@@ -428,12 +421,7 @@ function format(obj, sub, color, shell) {
           formatDate(x, key, shell);
         } else if (_constructorName === 'ClientSession') {
           x[key] = inspectable('ClientSession("' +
-            (
-              x[key] &&
-              x[key].id &&
-              x[key].id.id &&
-              x[key].id.id.buffer || ''
-            ).toString('hex') + '")');
+            (x[key]?.id?.id?.buffer || '').toString('hex') + '")');
         } else if (Array.isArray(x[key])) {
           x[key] = x[key].map(map);
         } else if (error != null) {

lib/drivers/node-mongodb-native/connection.js

@@ -316,15 +316,15 @@ NativeConnection.prototype.createClient = async function createClient(uri, optio
 
   const { schemaMap, encryptedFieldsMap } = this._buildEncryptionSchemas();
 
-  if ((Object.keys(schemaMap).length > 0 || Object.keys(encryptedFieldsMap).length) && !options.autoEncryption) {
+  if ((utils.hasOwnKeys(schemaMap) || utils.hasOwnKeys(encryptedFieldsMap)) && !options.autoEncryption) {
     throw new Error('Must provide `autoEncryption` when connecting with encrypted schemas.');
   }
 
-  if (Object.keys(schemaMap).length > 0) {
+  if (utils.hasOwnKeys(schemaMap)) {
     options.autoEncryption.schemaMap = schemaMap;
   }
 
-  if (Object.keys(encryptedFieldsMap).length > 0) {
+  if (utils.hasOwnKeys(encryptedFieldsMap)) {
     options.autoEncryption.encryptedFieldsMap = encryptedFieldsMap;
   }
 
@@ -435,18 +435,8 @@ function _setClient(conn, client, options, dbName) {
   const db = dbName != null ? client.db(dbName) : client.db();
   conn.db = db;
   conn.client = client;
-  conn.host = client &&
-    client.s &&
-    client.s.options &&
-    client.s.options.hosts &&
-    client.s.options.hosts[0] &&
-    client.s.options.hosts[0].host || void 0;
-  conn.port = client &&
-    client.s &&
-    client.s.options &&
-    client.s.options.hosts &&
-    client.s.options.hosts[0] &&
-    client.s.options.hosts[0].port || void 0;
+  conn.host = client?.s?.options?.hosts?.[0]?.host;
+  conn.port = client?.s?.options?.hosts?.[0]?.port;
   conn.name = dbName != null ? dbName : db.databaseName;
   conn._closeCalled = client._closeCalled;
 
@@ -463,10 +453,7 @@ function _setClient(conn, client, options, dbName) {
     }
   };
 
-  const type = client &&
-  client.topology &&
-  client.topology.description &&
-  client.topology.description.type || '';
+  const type = client?.topology?.description?.type || '';
 
   if (type === 'Single') {
     client.on('serverDescriptionChanged', ev => {

lib/helpers/document/applyTimestamps.js

@@ -2,6 +2,7 @@
 
 const handleTimestampOption = require('../schema/handleTimestampOption');
 const mpath = require('mpath');
+const utils = require('../../utils');
 
 module.exports = applyTimestamps;
 
@@ -71,7 +72,7 @@ function applyTimestampsToDoc(schema, obj, options) {
     return;
   }
 
-  if (schema.discriminators && Object.keys(schema.discriminators).length > 0) {
+  if (schema.discriminators && utils.hasOwnKeys(schema.discriminators)) {
     for (const discriminatorKey of Object.keys(schema.discriminators)) {
       const discriminator = schema.discriminators[discriminatorKey];
       const key = discriminator.discriminatorMapping.key;

lib/helpers/document/applyVirtuals.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const mpath = require('mpath');
+const utils = require('../../utils');
 
 module.exports = applyVirtuals;
 
@@ -101,7 +102,7 @@ function applyVirtualsToDoc(schema, obj, virtuals) {
     return;
   }
 
-  if (schema.discriminators && Object.keys(schema.discriminators).length > 0) {
+  if (schema.discriminators && utils.hasOwnKeys(schema.discriminators)) {
     for (const discriminatorKey of Object.keys(schema.discriminators)) {
       const discriminator = schema.discriminators[discriminatorKey];
       const key = discriminator.discriminatorMapping.key;

lib/helpers/document/compile.js

@@ -46,7 +46,7 @@ function compile(tree, proto, prefix, options) {
     const limb = tree[key];
 
     const hasSubprops = isPOJO(limb) &&
-      Object.keys(limb).length > 0 &&
+      utils.hasOwnKeys(limb) &&
       (!limb[typeKey] || (typeKey === 'type' && isPOJO(limb.type) && limb.type.type));
     const subprops = hasSubprops ? limb : null;
 
@@ -132,7 +132,7 @@ function defineKey({ prop, subprops, prototype, prefix, options }) {
             writable: false,
             value: function() {
               return _this.get(path, null, {
-                virtuals: this && this.schema && this.schema.options && this.schema.options.toObject && this.schema.options.toObject.virtuals || null
+                virtuals: this?.schema?.options?.toObject?.virtuals || null
               });
             }
           });
@@ -143,7 +143,7 @@ function defineKey({ prop, subprops, prototype, prefix, options }) {
             writable: false,
             value: function() {
               return _this.get(path, null, {
-                virtuals: this && this.schema && this.schema.options && this.schema.options.toJSON && this.schema.options.toJSON.virtuals || null
+                virtuals: this?.schema?.options?.toJSON?.virtuals || null
               });
             }
           });

lib/helpers/populate/getModelsMapForPopulate.js

@@ -26,6 +26,7 @@ module.exports = function getModelsMapForPopulate(model, docs, options) {
   let schema;
   let refPath;
   let modelNames;
+  let modelNamesSet;
   const available = {};
 
   const modelSchema = model.schema;
@@ -123,8 +124,10 @@ module.exports = function getModelsMapForPopulate(model, docs, options) {
           continue;
         }
         modelNames = modelNames || [];
+        modelNamesSet = modelNamesSet || new Set();
         for (const modelName of _modelNames) {
-          if (modelNames.indexOf(modelName) === -1) {
+          if (modelNamesSet.has(modelName) === false) {
+            modelNamesSet.add(modelName);
             modelNames.push(modelName);
           }
         }
@@ -225,8 +228,8 @@ module.exports = function getModelsMapForPopulate(model, docs, options) {
       schema = schema.$__schemaType;
     }
 
-    const ref = schema && schema.options && schema.options.ref;
-    refPath = schema && schema.options && schema.options.refPath;
+    const ref = schema?.options?.ref;
+    refPath = schema?.options?.refPath;
     if (schema != null &&
         schema[schemaMixedSymbol] &&
         !ref &&
@@ -721,7 +724,7 @@ function _findRefPathForDiscriminators(doc, modelSchema, data, options, normaliz
     if (schematype != null &&
         schematype.$isMongooseDocumentArray &&
         schematype.Constructor.discriminators != null &&
-        Object.keys(schematype.Constructor.discriminators).length !== 0) {
+        utils.hasOwnKeys(schematype.Constructor.discriminators)) {
       const subdocs = utils.getValue(cur, doc);
       const remnant = options.path.substring(cur.length + 1);
       const discriminatorKey = schematype.Constructor.schema.options.discriminatorKey;