diff --git a/index.js b/index.js
index 029571e..82cab92 100644
--- a/index.js
+++ b/index.js
@@ -12,9 +12,7 @@ var indexesCache = {};
  * @return {bool} True if and only if it is an unique error.
  */
 function isUniqueError(err) {
-    return err
-        && (err.name === 'BulkWriteError' || err.name === 'MongoError')
-        && (err.code === 11000 || err.code === 11001);
+  return err && ['BulkWriteError', 'MongoError', 'MongoServerError'].includes(err.name) && (err.code === 11000 || err.code === 11001);
 }
 
 /**
@@ -29,20 +27,14 @@ function isUniqueError(err) {
  * @return {*} Matching value, or undefined if none.
  */
 function getValueByPath(obj, path) {
-    var segments = path.split('.');
-    var result = obj;
-
-    for (
-        var i = 0;
-        i < segments.length
-            && result !== null
-            && result !== undefined;
-        ++i
-    ) {
-        result = result[segments[i]];
-    }
+  var segments = path.split('.');
+  var result = obj;
+
+  for (var i = 0; i < segments.length && result !== null && result !== undefined; ++i) {
+    result = result[segments[i]];
+  }
 
-    return result;
+  return result;
 }
 
 /**
@@ -53,34 +45,31 @@ function getValueByPath(obj, path) {
  * @return {Object} Map of collected messages.
  */
 function collectMessages(tree) {
-    var result = {};
-
-    for (var key in tree) {
-        if (tree.hasOwnProperty(key)) {
-            if (
-                typeof tree[key] === 'object'
-                && tree[key] !== null
-            ) {
-                if (typeof tree[key].unique === 'string') {
-                    // Schema property that has a custom
-                    // unique message
-                    result[key] = tree[key].unique;
-                    tree[key].unique = true;
-                } else {
-                    // Nested schema
-                    var subtree = collectMessages(tree[key]);
-
-                    for (var subkey in subtree) {
-                        if (subtree.hasOwnProperty(subkey)) {
-                            result[key + '.' + subkey] = subtree[subkey];
-                        }
-                    }
-                }
+  var result = {};
+
+  for (var key in tree) {
+    if (tree.hasOwnProperty(key)) {
+      if (typeof tree[key] === 'object' && tree[key] !== null) {
+        if (typeof tree[key].unique === 'string') {
+          // Schema property that has a custom
+          // unique message
+          result[key] = tree[key].unique;
+          tree[key].unique = true;
+        } else {
+          // Nested schema
+          var subtree = collectMessages(tree[key]);
+
+          for (var subkey in subtree) {
+            if (subtree.hasOwnProperty(subkey)) {
+              result[key + '.' + subkey] = subtree[subkey];
             }
+          }
         }
+      }
     }
+  }
 
-    return result;
+  return result;
 }
 
 /**
@@ -91,22 +80,22 @@ function collectMessages(tree) {
  * @return {Promise} Resolved with index information data.
  */
 function getIndexes(collection) {
-    return new global.Promise(function (resolve, reject) {
-        if (indexesCache[collection.name]) {
-            resolve(indexesCache[collection.name]);
-            return;
-        }
+  return new global.Promise(function (resolve, reject) {
+    if (indexesCache[collection.name]) {
+      resolve(indexesCache[collection.name]);
+      return;
+    }
 
-        collection.indexInformation(function (dbErr, indexes) {
-            if (dbErr) {
-                reject(dbErr);
-                return;
-            }
+    collection.indexInformation(function (dbErr, indexes) {
+      if (dbErr) {
+        reject(dbErr);
+        return;
+      }
 
-            indexesCache[collection.name] = indexes;
-            resolve(indexes);
-        });
+      indexesCache[collection.name] = indexes;
+      resolve(indexes);
     });
+  });
 }
 
 /**
@@ -121,126 +110,119 @@ function getIndexes(collection) {
  * @return {Promise.<ValidationError>} Beautified error message
  */
 function beautify(error, collection, values, messages, defaultMessage) {
-    // Try to recover the list of duplicated fields
-    var onSuberrors = global.Promise.resolve({});
-
-    // Extract the failed duplicate index's name from the
-    // from the error message (with a hacky regex)
-    var matches = errorRegex.exec(error.message);
-
-    if (matches) {
-        var indexName = matches[1];
-
-        // Retrieve that index's list of fields
-        onSuberrors = getIndexes(collection).then(function (indexes) {
-            var suberrors = {};
-
-            // Create a suberror per duplicated field
-            if (indexName in indexes) {
-                indexes[indexName].forEach(function (field) {
-                    var path = field[0];
-                    var props = {
-                        type: 'unique',
-                        path: path,
-                        value: getValueByPath(values, path),
-                        message: typeof messages[path] === 'string'
-                            ? messages[path] : defaultMessage
-                    };
-
-                    suberrors[path] = new mongoose.Error.ValidatorError(props);
-                });
-            }
-
-            return suberrors;
+  // Try to recover the list of duplicated fields
+  var onSuberrors = global.Promise.resolve({});
+
+  // Extract the failed duplicate index's name from the
+  // from the error message (with a hacky regex)
+  var matches = errorRegex.exec(error.message);
+
+  if (matches) {
+    var indexName = matches[1];
+
+    // Retrieve that index's list of fields
+    onSuberrors = getIndexes(collection).then(function (indexes) {
+      var suberrors = {};
+
+      // Create a suberror per duplicated field
+      if (indexName in indexes) {
+        indexes[indexName].forEach(function (field) {
+          var path = field[0];
+          var props = {
+            type: 'unique',
+            path: path,
+            value: getValueByPath(values, path),
+            message: typeof messages[path] === 'string' ? messages[path] : defaultMessage,
+          };
+
+          suberrors[path] = new mongoose.Error.ValidatorError(props);
         });
-    }
-
-    return onSuberrors.then(function (suberrors) {
-        var beautifiedError = new mongoose.Error.ValidationError();
+      }
 
-        beautifiedError.errors = suberrors;
-        return beautifiedError;
+      return suberrors;
     });
+  }
+
+  return onSuberrors.then(function (suberrors) {
+    var beautifiedError = new mongoose.Error.ValidationError();
+
+    beautifiedError.errors = suberrors;
+    return beautifiedError;
+  });
 }
 
 module.exports = function (schema, options) {
-    options = options || {};
+  options = options || {};
 
-    if (!options.defaultMessage) {
-        options.defaultMessage = 'Path `{PATH}` ({VALUE}) is not unique.';
-    }
+  if (!options.defaultMessage) {
+    options.defaultMessage = 'Path `{PATH}` ({VALUE}) is not unique.';
+  }
 
-    // Fetch error messages defined in the "unique" field,
-    // store them for later use and replace them with true
-    var tree = schema.tree;
-    var messages = collectMessages(tree);
+  // Fetch error messages defined in the "unique" field,
+  // store them for later use and replace them with true
+  var tree = schema.tree;
+  var messages = collectMessages(tree);
 
-    schema._indexes.forEach(function (index) {
-        if (index[0] && index[1] && index[1].unique) {
-            Object.keys(index[0]).forEach(function (indexKey) {
-                messages[indexKey] = index[1].unique;
-            });
+  schema._indexes.forEach(function (index) {
+    if (index[0] && index[1] && index[1].unique) {
+      Object.keys(index[0]).forEach(function (indexKey) {
+        messages[indexKey] = index[1].unique;
+      });
 
-            index[1].unique = true;
-        }
-    });
+      index[1].unique = true;
+    }
+  });
+
+  // Post hook that gets called after any save or update
+  // operation and that filters unique errors
+  var postHook = function (error, _, next) {
+    // Mongoose ≥5 does no longer pass the document as the
+    // second argument of 'update' hooks, so we use this instead
+    var doc = this;
+
+    // If the next() function is missing, this might be
+    // a sign that we are using an outdated Mongoose
+    if (typeof next !== 'function') {
+      throw new Error(
+        'mongoose-beautiful-unique-validation error: ' +
+          'The hook was called incorrectly. Double check that ' +
+          'you are using mongoose@>=4.5.0; if you need to use ' +
+          'an outdated Mongoose version, please install this module ' +
+          'in version 4.0.0'
+      );
+    }
 
-    // Post hook that gets called after any save or update
-    // operation and that filters unique errors
-    var postHook = function (error, _, next) {
-        // Mongoose ≥5 does no longer pass the document as the
-        // second argument of 'update' hooks, so we use this instead
-        var doc = this;
-
-        // If the next() function is missing, this might be
-        // a sign that we are using an outdated Mongoose
-        if (typeof next !== 'function') {
-            throw new Error(
-                'mongoose-beautiful-unique-validation error: '
-                + 'The hook was called incorrectly. Double check that '
-                + 'you are using mongoose@>=4.5.0; if you need to use '
-                + 'an outdated Mongoose version, please install this module '
-                + 'in version 4.0.0'
-            );
-        }
+    if (isUniqueError(error)) {
+      // Beautify unicity constraint failure errors
+      var collection, values;
 
-        if (isUniqueError(error)) {
-            // Beautify unicity constraint failure errors
-            var collection, values;
-
-            if (this.constructor.name == 'Query') {
-                collection = this.model.collection;
-                values = this._update;
-
-                if ('$set' in values) {
-                    values = Object.assign({}, values, values.$set);
-                    delete values.$set;
-                }
-            } else {
-                collection = doc.collection;
-                values = doc;
-            }
+      if (this.constructor.name == 'Query') {
+        collection = this.model.collection;
+        values = this._update;
 
-            beautify(
-                error, collection, values,
-                messages, options.defaultMessage
-            )
-                .then(next)
-                .catch(function (beautifyError) {
-                    setTimeout(function () {
-                        throw new Error(
-                            'mongoose-beautiful-unique-validation error: '
-                            + beautifyError.stack
-                        );
-                    });
-                });
-        } else {
-            // Pass over other errors
-            next(error);
+        if ('$set' in values) {
+          values = Object.assign({}, values, values.$set);
+          delete values.$set;
         }
-    };
+      } else {
+        collection = doc.collection;
+        values = doc;
+      }
+
+      beautify(error, collection, values, messages, options.defaultMessage)
+        .then(next)
+        .catch(function (beautifyError) {
+          setTimeout(function () {
+            throw new Error('mongoose-beautiful-unique-validation error: ' + beautifyError.stack);
+          });
+        });
+    } else {
+      // Pass over other errors
+      next(error);
+    }
+  };
 
-    schema.post('save', postHook);
-    schema.post('update', postHook);
-    schema.post('findOneAndUpdate', postHook);
+  schema.post('save', postHook);
+  schema.post('update', postHook);
+  schema.post('findOneAndUpdate', postHook);
 };
diff --git a/package.json b/package.json
index 75708c7..84cc54c 100644
--- a/package.json
+++ b/package.json
@@ -1,12 +1,12 @@
 {
   "name": "mongoose-beautiful-unique-validation",
   "description": "Plugin for Mongoose that turns duplicate errors into regular Mongoose validation errors",
-  "version": "7.1.1",
+  "version": "7.1.2",
   "license": "MIT",
   "main": "index.js",
   "repository": {
     "type": "git",
-    "url": "https://github.com/matteodelabre/mongoose-beautiful-unique-validation.git"
+    "url": "https://github.com/OguzBey/mongoose-beautiful-unique-validation.git"
   },
   "scripts": {
     "test": "tape tests | tap-spec",
@@ -23,9 +23,9 @@
     "unique"
   ],
   "author": {
-    "name": "Mattéo Delabre ✏️",
-    "email": "contact@matteodelabre.me",
-    "url": "https://github.com/matteodelabre"
+    "name": "Oğuzhan",
+    "email": "cfmelun@gmail.com",
+    "url": "https://github.com/OguzBey"
   },
   "peerDependencies": {
     "mongoose": ">=4.11.4"