diff --git a/application/Espo/Resources/metadata/clientDefs/EmailAccount.json b/application/Espo/Resources/metadata/clientDefs/EmailAccount.json
index 05436532bd..0e4e00e78b 100644
--- a/application/Espo/Resources/metadata/clientDefs/EmailAccount.json
+++ b/application/Espo/Resources/metadata/clientDefs/EmailAccount.json
@@ -1,5 +1,4 @@
 {
-    "controller": "controllers/email-account",
     "recordViews": {
         "list":"views/email-account/record/list",
         "detail": "views/email-account/record/detail",
diff --git a/client/src/controllers/about.js b/client/src/controllers/about.js
index c1919bc567..f485549fd2 100644
--- a/client/src/controllers/about.js
+++ b/client/src/controllers/about.js
@@ -26,16 +26,18 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/about', ['controller'], function (Dep) {
+import Controller from 'controller';
 
-    return Dep.extend({
+class AboutController extends Controller {
 
-        defaultAction: 'about',
+    defaultAction = 'about'
 
-        actionAbout: function () {
-            this.main('About', {}, function (view) {
-                view.render();
-            });
-        },
-    });
-});
+    // noinspection JSUnusedGlobalSymbols
+    actionAbout() {
+        this.main('About', {}, view => {
+            view.render();
+        });
+    }
+}
+
+export default AboutController;
diff --git a/client/src/controllers/address-map.js b/client/src/controllers/address-map.js
index cf48edfd8d..9a0224c569 100644
--- a/client/src/controllers/address-map.js
+++ b/client/src/controllers/address-map.js
@@ -26,34 +26,39 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/address-map', ['controller'], function (Dep) {
+import Controller from 'controller';
 
-    return Dep.extend({
+class AddressMapController extends Controller {
 
-        defaultAction: 'index',
+    defaultAction = 'index'
 
-        actionIndex: function () {
-            this.error404();
-        },
+    // noinspection JSUnusedGlobalSymbols
+    actionIndex() {
+        this.error404();
+    }
 
-        actionView: function (o) {
-            this.modelFactory.create(o.entityType)
-            .then(
-                function (model) {
-                    model.id = o.id;
-                    model.fetch().then(
-                        function () {
-                            var viewName = this.getMetadata().get(['AddressMap', 'view']) ||
-                                'views/address-map/view';
+    // noinspection JSUnusedGlobalSymbols
+    /**
+     * @param {Object} o
+     */
+    actionView(o) {
+        this.modelFactory
+            .create(o.entityType)
+            .then(model => {
+                model.id = o.id;
 
-                            this.main(viewName, {
-                                model: model,
-                                field: o.field,
-                            });
-                        }.bind(this)
-                    );
-                }.bind(this)
-            );
-        },
-    });
-});
+                model.fetch()
+                    .then(() => {
+                        let viewName = this.getMetadata().get(['AddressMap', 'view']) ||
+                            'views/address-map/view';
+
+                        this.main(viewName, {
+                            model: model,
+                            field: o.field,
+                        });
+                    });
+            });
+    }
+}
+
+export default AddressMapController;
diff --git a/client/src/controllers/dashboard.js b/client/src/controllers/dashboard.js
index 4b5638c08f..865b83ed8d 100644
--- a/client/src/controllers/dashboard.js
+++ b/client/src/controllers/dashboard.js
@@ -26,18 +26,20 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/dashboard', ['controller'], function (Dep) {
+import Controller from 'controller';
 
-    return Dep.extend({
+class DashboardController extends Controller {
 
-        defaultAction: 'index',
+    defaultAction = 'index'
 
-        actionIndex: function () {
-            this.main('views/dashboard', {
-                displayTitle: true,
-            }, (view) => {
-                view.render();
-            });
-        },
-    });
-});
+    // noinspection JSUnusedGlobalSymbols
+    actionIndex() {
+        this.main('views/dashboard', {
+            displayTitle: true,
+        }, view => {
+            view.render();
+        });
+    }
+}
+
+export default DashboardController;
diff --git a/client/src/controllers/email-account.js b/client/src/controllers/email-account.js
deleted file mode 100644
index f6a384a98f..0000000000
--- a/client/src/controllers/email-account.js
+++ /dev/null
@@ -1,34 +0,0 @@
-/************************************************************************
- * This file is part of EspoCRM.
- *
- * EspoCRM - Open Source CRM application.
- * Copyright (C) 2014-2023 Yurii Kuznietsov, Taras Machyshyn, Oleksii Avramenko
- * Website: https://www.espocrm.com
- *
- * EspoCRM is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * EspoCRM is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
- *
- * The interactive user interfaces in modified source and object code versions
- * of this program must display Appropriate Legal Notices, as required under
- * Section 5 of the GNU General Public License version 3.
- *
- * In accordance with Section 7(b) of the GNU General Public License version 3,
- * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
- ************************************************************************/
-
-define('controllers/email-account', ['controllers/record'], function (Dep) {
-
-    return Dep.extend({
-
-    });
-});
diff --git a/client/src/controllers/email.js b/client/src/controllers/email.js
index 2317255bdd..b07e7805be 100644
--- a/client/src/controllers/email.js
+++ b/client/src/controllers/email.js
@@ -26,21 +26,22 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/email', ['controllers/record'], function (Dep) {
+import RecordController from 'controllers/record';
 
-    return Dep.extend({
+class EmailController extends RecordController {
 
-        prepareModelView: function (model, options) {
-            Dep.prototype.prepareModelView(model, options);
+    prepareModelView(model, options) {
+        super.prepareModelView(model, options);
 
-            this.listenToOnce(model, 'after:send', () => {
-                let key = this.name + 'List';
-                let stored = this.getStoredMainView(key);
+        this.listenToOnce(model, 'after:send', () => {
+            let key = this.name + 'List';
+            let stored = this.getStoredMainView(key);
 
-                if (stored) {
-                    this.clearStoredMainView(key);
-                }
-            });
-        },
-    });
-});
+            if (stored) {
+                this.clearStoredMainView(key);
+            }
+        });
+    }
+}
+
+export default EmailController;
diff --git a/client/src/controllers/external-account.js b/client/src/controllers/external-account.js
index b962cee34f..3a953070bf 100644
--- a/client/src/controllers/external-account.js
+++ b/client/src/controllers/external-account.js
@@ -26,37 +26,41 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/external-account', ['controller'], function (Dep) {
+import Controller from 'controller';
 
-    return Dep.extend({
+class ExternalAccountController extends Controller {
 
-        defaultAction: 'list',
+    defaultAction = 'list'
 
-        actionList: function (options) {
-            this.collectionFactory.create('ExternalAccount', (collection) => {
-                collection.once('sync', () => {
-                    this.main('ExternalAccount.Index', {
-                        collection: collection,
-                    });
+    actionList() {
+        this.collectionFactory.create('ExternalAccount', collection => {
+            collection.once('sync', () => {
+                this.main('ExternalAccount.Index', {
+                    collection: collection,
                 });
-
-                collection.fetch();
             });
-        },
 
-        actionEdit: function (options) {
-            let id = options.id;
+            collection.fetch();
+        });
+    }
 
-            this.collectionFactory.create('ExternalAccount', (collection) => {
-                collection.once('sync', () => {
-                    this.main('ExternalAccount.Index', {
-                        collection: collection,
-                        id: id,
-                    });
+    /**
+     * @param {{id: string}} options
+     */
+    actionEdit(options) {
+        let id = options.id;
+
+        this.collectionFactory.create('ExternalAccount', collection => {
+            collection.once('sync', () => {
+                this.main('ExternalAccount.Index', {
+                    collection: collection,
+                    id: id,
                 });
-
-                collection.fetch();
             });
-        },
-    });
-});
+
+            collection.fetch();
+        });
+    }
+}
+
+export default ExternalAccountController;
diff --git a/client/src/controllers/home.js b/client/src/controllers/home.js
index cf59753d83..72800e9a84 100644
--- a/client/src/controllers/home.js
+++ b/client/src/controllers/home.js
@@ -26,12 +26,14 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/home', ['controller'], function (Dep) {
+import Controller from 'controller';
 
-    return Dep.extend({
+class HomeController extends Controller {
 
-        actionIndex: function () {
-            this.main('views/home', null);
-        },
-    });
-});
+    // noinspection JSUnusedGlobalSymbols
+    actionIndex() {
+        this.main('views/home', null);
+    }
+}
+
+export default HomeController;
diff --git a/client/src/controllers/import.js b/client/src/controllers/import.js
index 44e21b25e7..953a503c87 100644
--- a/client/src/controllers/import.js
+++ b/client/src/controllers/import.js
@@ -26,71 +26,79 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('controllers/import', ['controllers/record'], function (Dep) {
+import RecordController from 'controllers/record';
 
-    return Dep.extend({
+class ImportController extends RecordController {
 
-        defaultAction: 'index',
+    defaultAction = 'index'
 
-        checkAccessGlobal: function () {
-            if (this.getAcl().checkScope('Import')) {
-                return true;
-            }
+    checkAccessGlobal() {
+        if (this.getAcl().checkScope('Import')) {
+            return true;
+        }
 
-            return false;
-        },
+        return false;
+    }
 
-        checkAccess: function () {
-            if (this.getAcl().checkScope('Import')) {
-                return true;
-            }
+    checkAccess(action) {
+        if (this.getAcl().checkScope('Import')) {
+            return true;
+        }
 
-            return false;
-        },
+        return false;
+    }
 
-        actionIndex: function (o) {
-            o = o || {};
+    // noinspection JSUnusedGlobalSymbols
+    /**
+     * @param {{
+     *     step?: int|string,
+     *     fromAdmin?: boolean,
+     *     formData?: Object
+     * }} o
+     */
+    actionIndex(o) {
+        o = o || {};
 
-            var step = null;
+        let step = null;
 
-            if (o.step) {
-                step = parseInt(step);
-            }
+        if (o.step) {
+            step = parseInt(step);
+        }
 
-            var formData = null;
-            var fileContents = null;
+        let formData = null;
+        let fileContents = null;
 
-            if (this.storedData) {
-                formData = this.storedData.formData;
-                fileContents = this.storedData.fileContents;
-            }
+        if (this.storedData) {
+            formData = this.storedData.formData;
+            fileContents = this.storedData.fileContents;
+        }
 
-            if (!formData) {
-                step = null;
-            }
+        if (!formData) {
+            step = null;
+        }
 
-            formData = formData || o.formData;
+        formData = formData || o.formData;
 
-            this.main('views/import/index', {
-                step: step,
-                formData: formData,
-                fileContents: fileContents,
-                fromAdmin: o.fromAdmin,
-            }, (view) => {
-                this.listenTo(view, 'change', () => {
-                    this.storedData = {
-                        formData: view.formData,
-                        fileContents: view.fileContents,
-                    };
-                });
-
-                this.listenTo(view, 'done', () => {
-                    delete this.storedData;
-                });
-
-                view.render();
+        this.main('views/import/index', {
+            step: step,
+            formData: formData,
+            fileContents: fileContents,
+            fromAdmin: o.fromAdmin,
+        }, /** module:views/import/index */ view => {
+            this.listenTo(view, 'change', () => {
+                this.storedData = {
+                    formData: view.formData,
+                    fileContents: view.fileContents,
+                };
             });
-        },
 
-    });
-});
+            this.listenTo(view, 'done', () => {
+                delete this.storedData;
+            });
+
+            view.render();
+        });
+    }
+}
+
+export default ImportController;
diff --git a/client/src/field-manager.js b/client/src/field-manager.js
index 66918f1b84..390379eea7 100644
--- a/client/src/field-manager.js
+++ b/client/src/field-manager.js
@@ -80,7 +80,7 @@ class FieldManager {
      * Get a list of parameters for a specific field type.
      *
      * @param {string} fieldType A field type.
-     * @returns {string[]}
+     * @returns {Object.<string, *>[]}
      */
     getParamList(fieldType) {
         if (fieldType in this.defs) {
diff --git a/client/src/handlers/create-related.js b/client/src/handlers/create-related.js
index 9854cb2b90..e96e09d45f 100644
--- a/client/src/handlers/create-related.js
+++ b/client/src/handlers/create-related.js
@@ -26,36 +26,31 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('handlers/create-related', [], () => {
+/**
+ * Prepares attributes for a related record that is being created.
+ *
+ * @abstract
+ */
+class CreateRelatedHandler {
 
     /**
-     * Prepares attributes for a related record that is being created.
-     *
-     * @abstract
-     * @class
-     * @name Class
-     * @memberOf module:handlers/create-related
+     * @param {module:view-helper} viewHelper
      */
-    class Class {
-
-        /**
-         * @param {module:view-helper} viewHelper
-         */
-        constructor(viewHelper) {
-            this.viewHelper = viewHelper;
-        }
-
-        /**
-         * Get attributes for a new record.
-         *
-         * @abstract
-         * @param {module:model} model A model.
-         * @return {Promise<Object.<string, *>>} Attributes.
-         */
-        getAttributes(model) {
-            return Promise.resolve({});
-        }
+    constructor(viewHelper) {
+        // noinspection JSUnusedGlobalSymbols
+        this.viewHelper = viewHelper;
     }
 
-    return Class;
-});
+    /**
+     * Get attributes for a new record.
+     *
+     * @abstract
+     * @param {module:model} model A model.
+     * @return {Promise<Object.<string, *>>} Attributes.
+     */
+    getAttributes(model) {
+        return Promise.resolve({});
+    }
+}
+
+export default CreateRelatedHandler;
diff --git a/client/src/handlers/email-filter.js b/client/src/handlers/email-filter.js
index d3e02a2865..7298626a3a 100644
--- a/client/src/handlers/email-filter.js
+++ b/client/src/handlers/email-filter.js
@@ -26,101 +26,101 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('handlers/email-filter', ['dynamic-handler'], (Dep) => {
+import DynamicHandler from 'dynamic-handler';
 
-    return Dep.extend({
+class EmailFilterHandler extends DynamicHandler {
 
-        init: function () {
-            if (this.model.isNew()) {
-                if (!this.recordView.getUser().isAdmin()) {
-                    this.recordView.hideField('isGlobal');
-                }
-            }
-
-            if (
-                !this.model.isNew() &&
-                !this.recordView.getUser().isAdmin() &&
-                !this.model.get('isGlobal')
-            ) {
+    init() {
+        if (this.model.isNew()) {
+            if (!this.recordView.getUser().isAdmin()) {
                 this.recordView.hideField('isGlobal');
             }
+        }
 
-            if (this.model.isNew() && !this.model.get('parentId')) {
-                this.model.set('parentType', 'User');
-                this.model.set('parentId', this.recordView.getUser().id);
-                this.model.set('parentName', this.recordView.getUser().get('name'));
+        if (
+            !this.model.isNew() &&
+            !this.recordView.getUser().isAdmin() &&
+            !this.model.get('isGlobal')
+        ) {
+            this.recordView.hideField('isGlobal');
+        }
 
-                if (!this.recordView.getUser().isAdmin()) {
-                    this.recordView.setFieldReadOnly('parent');
-                }
-            }
-            else if (
-                this.model.get('parentType') &&
-                !this.recordView.options.duplicateSourceId
-            ) {
+        if (this.model.isNew() && !this.model.get('parentId')) {
+            this.model.set('parentType', 'User');
+            this.model.set('parentId', this.recordView.getUser().id);
+            this.model.set('parentName', this.recordView.getUser().get('name'));
+
+            if (!this.recordView.getUser().isAdmin()) {
                 this.recordView.setFieldReadOnly('parent');
-                this.recordView.setFieldReadOnly('isGlobal');
+            }
+        }
+        else if (
+            this.model.get('parentType') &&
+            !this.recordView.options.duplicateSourceId
+        ) {
+            this.recordView.setFieldReadOnly('parent');
+            this.recordView.setFieldReadOnly('isGlobal');
+        }
+
+        this.recordView.listenTo(this.model, 'change:isGlobal', (model, value, o) => {
+            if (!o.ui) {
+                return;
             }
 
-            this.recordView.listenTo(this.model, 'change:isGlobal', (model, value, o) => {
-                if (!o.ui) {
+            if (value) {
+                this.model.set({
+                    action: 'Skip',
+                    parentName: null,
+                    parentType: null,
+                    parentId: null,
+                    emailFolderId: null,
+                    groupEmailFolderId: null,
+                    markAsRead: false,
+                });
+            }
+        });
+
+        this.recordView.listenTo(this.model, 'change:parentType', (model, value, o) => {
+            if (!o.ui) {
+                return;
+            }
+
+            // Avoiding side effects.
+            setTimeout(() => {
+                if (value !== 'User') {
+                    this.model.set('markAsRead', false);
+                }
+
+                if (value === 'EmailAccount') {
+                    this.model.set('action', 'Skip');
+                    this.model.set('emailFolderId', null);
+                    this.model.set('groupEmailFolderId', null);
+                    this.model.set('markAsRead', false);
+
                     return;
                 }
 
-                if (value) {
-                    this.model.set({
-                        action: 'Skip',
-                        parentName: null,
-                        parentType: null,
-                        parentId: null,
-                        emailFolderId: null,
-                        groupEmailFolderId: null,
-                        markAsRead: false,
-                    });
-                }
-            });
-
-            this.recordView.listenTo(this.model, 'change:parentType', (model, value, o) => {
-                if (!o.ui) {
-                    return;
-                }
-
-                // Avoiding side effects.
-                setTimeout(() => {
-                    if (value !== 'User') {
-                        this.model.set('markAsRead', false);
-                    }
-
-                    if (value === 'EmailAccount') {
+                if (value !== 'InboundEmail') {
+                    if (this.model.get('action') === 'Move to Group Folder') {
                         this.model.set('action', 'Skip');
-                        this.model.set('emailFolderId', null);
-                        this.model.set('groupEmailFolderId', null);
-                        this.model.set('markAsRead', false);
-
-                        return;
                     }
 
-                    if (value !== 'InboundEmail') {
-                        if (this.model.get('action') === 'Move to Group Folder') {
-                            this.model.set('action', 'Skip');
-                        }
+                    this.model.set('groupEmailFolderId', null);
 
-                        this.model.set('groupEmailFolderId', null);
+                    return;
+                }
 
-                        return;
+                if (value !== 'User') {
+                    if (this.model.get('action') === 'Move to Folder') {
+                        this.model.set('action', 'Skip');
                     }
 
-                    if (value !== 'User') {
-                        if (this.model.get('action') === 'Move to Folder') {
-                            this.model.set('action', 'Skip');
-                        }
+                    this.model.set('groupFolderId', null);
+                }
+            }, 40);
+        });
+    }
+}
 
-                        this.model.set('groupFolderId', null);
+export default EmailFilterHandler;
 
-                        return;
-                    }
-                }, 40);
-            });
-        },
-    });
-});
diff --git a/client/src/handlers/import.js b/client/src/handlers/import.js
index a42d05b69e..b11fc6e569 100644
--- a/client/src/handlers/import.js
+++ b/client/src/handlers/import.js
@@ -26,29 +26,26 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('handlers/import', ['action-handler'], function (Dep) {
+import ActionHandler from 'action-handler';
 
-    /**
-     * @extends module:action-handler
-     */
-    class Class extends Dep {
+class ImportHandler extends ActionHandler {
 
-        actionErrorExport() {
-            Espo.Ajax
-                .postRequest(`Import/${this.view.model.id}/exportErrors`)
-                .then(data => {
-                    if (!data.attachmentId) {
-                        let message = this.view.translate('noErrors', 'messages', 'Import');
+    // noinspection JSUnusedGlobalSymbols
+    actionErrorExport() {
+        Espo.Ajax
+            .postRequest(`Import/${this.view.model.id}/exportErrors`)
+            .then(data => {
+                if (!data.attachmentId) {
+                    let message = this.view.translate('noErrors', 'messages', 'Import');
 
-                        Espo.Ui.warning(message);
+                    Espo.Ui.warning(message);
 
-                        return;
-                    }
+                    return;
+                }
 
-                    window.location = this.view.getBasePath() + '?entryPoint=download&id=' + data.attachmentId;
-                });
-        }
+                window.location = this.view.getBasePath() + '?entryPoint=download&id=' + data.attachmentId;
+            });
     }
+}
 
-    return Class;
-});
+export default ImportHandler;
diff --git a/client/src/handlers/login.js b/client/src/handlers/login.js
index 160605e6f4..7b2243fd8b 100644
--- a/client/src/handlers/login.js
+++ b/client/src/handlers/login.js
@@ -33,7 +33,7 @@
  *
  * @abstract
  */
-class Handler {
+class LoginHandler {
 
     /**
      * @param {module:views/login} loginView A login view.
@@ -67,4 +67,4 @@ class Handler {
     }
 }
 
-export default Handler;
+export default LoginHandler;
diff --git a/client/src/handlers/login/oidc.js b/client/src/handlers/login/oidc.js
index eb29d99b6f..19a3c5463a 100644
--- a/client/src/handlers/login/oidc.js
+++ b/client/src/handlers/login/oidc.js
@@ -26,10 +26,10 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-import Dep from 'handlers/login';
+import LoginHandler from 'handlers/login';
 import Base64 from 'js-base64';
 
-class Handler extends Dep {
+class OidcLoginHandler extends LoginHandler {
 
     /** @inheritDoc */
     process() {
@@ -209,4 +209,4 @@ class Handler extends Dep {
     }
 }
 
-export default Handler;
+export default OidcLoginHandler;
diff --git a/client/src/handlers/select-related.js b/client/src/handlers/select-related.js
index 03697bc9ee..b3f9d86223 100644
--- a/client/src/handlers/select-related.js
+++ b/client/src/handlers/select-related.js
@@ -42,12 +42,13 @@
  *
  * @abstract
  */
-class SelectRelated {
+class SelectRelatedHandler {
 
     /**
      * @param {module:view-helper} viewHelper
      */
     constructor(viewHelper) {
+        // noinspection JSUnusedGlobalSymbols
         /** @protected */
         this.viewHelper = viewHelper;
     }
@@ -64,4 +65,4 @@ class SelectRelated {
     }
 }
 
-export default SelectRelated;
+export default SelectRelatedHandler;
diff --git a/client/src/handlers/select-related/same-account-many.js b/client/src/handlers/select-related/same-account-many.js
index 8b11821154..e8c8924d3d 100644
--- a/client/src/handlers/select-related/same-account-many.js
+++ b/client/src/handlers/select-related/same-account-many.js
@@ -26,44 +26,47 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('handlers/select-related/same-account-many', ['handlers/select-related'], Dep => {
+import SelectRelatedHandler from 'handlers/select-related';
 
-    return class extends Dep {
-        /**
-         * @param {module:model} model
-         * @return {Promise<module:handlers/select-related~filters>}
-         */
-        getFilters(model) {
-            let advanced = {};
+class SameAccountManySelectRelatedHandler extends SelectRelatedHandler {
 
-            let accountId = null;
-            let accountName = null;
+    /**
+     * @param {module:model} model
+     * @return {Promise<module:handlers/select-related~filters>}
+     */
+    getFilters(model) {
+        let advanced = {};
 
-            if (model.get('accountId')) {
-                accountId = model.get('accountId');
-                accountName = model.get('accountName');
-            }
+        let accountId = null;
+        let accountName = null;
 
-            if (!accountId && model.get('parentType') === 'Account' && model.get('parentId')) {
-                accountId = model.get('parentId');
-                accountName = model.get('parentName');
-            }
-
-            if (accountId) {
-                let nameHash = {};
-                nameHash[accountId] = accountName;
-
-                advanced.accounts = {
-                    field: 'accounts',
-                    type: 'linkedWith',
-                    value: [accountId],
-                    data: {nameHash: nameHash},
-                };
-            }
-
-            return Promise.resolve({
-                advanced: advanced,
-            });
+        if (model.get('accountId')) {
+            accountId = model.get('accountId');
+            accountName = model.get('accountName');
         }
+
+        if (!accountId && model.get('parentType') === 'Account' && model.get('parentId')) {
+            accountId = model.get('parentId');
+            accountName = model.get('parentName');
+        }
+
+        if (accountId) {
+            let nameHash = {};
+            nameHash[accountId] = accountName;
+
+            advanced.accounts = {
+                field: 'accounts',
+                type: 'linkedWith',
+                value: [accountId],
+                data: {nameHash: nameHash},
+            };
+        }
+
+        return Promise.resolve({
+            advanced: advanced,
+        });
     }
-});
+}
+
+// noinspection JSUnusedGlobalSymbols
+export default SameAccountManySelectRelatedHandler;
diff --git a/client/src/handlers/select-related/same-account.js b/client/src/handlers/select-related/same-account.js
index 17d7405474..9d749529d3 100644
--- a/client/src/handlers/select-related/same-account.js
+++ b/client/src/handlers/select-related/same-account.js
@@ -26,44 +26,46 @@
  * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
  ************************************************************************/
 
-define('handlers/select-related/same-account', ['handlers/select-related'], Dep => {
+import SelectRelatedHandler from 'handlers/select-related';
 
-    return class extends Dep {
-        /**
-         * @param {module:model} model
-         * @return {Promise<module:handlers/select-related~filters>}
-         */
-        getFilters(model) {
-            let advanced = {};
+class SameAccountSelectRelatedHandler extends SelectRelatedHandler {
 
-            let accountId = null;
-            let accountName = null;
+    /**
+     * @param {module:model} model
+     * @return {Promise<module:handlers/select-related~filters>}
+     */
+    getFilters(model) {
+        let advanced = {};
 
-            if (model.get('accountId')) {
-                accountId = model.get('accountId');
-                accountName = model.get('accountName');
-            }
+        let accountId = null;
+        let accountName = null;
 
-            if (!accountId && model.get('parentType') === 'Account' && model.get('parentId')) {
-                accountId = model.get('parentId');
-                accountName = model.get('parentName');
-            }
-
-            if (accountId) {
-                advanced.account = {
-                    attribute: 'accountId',
-                    type: 'equals',
-                    value: accountId,
-                    data: {
-                        type: 'is',
-                        nameValue: accountName,
-                    },
-                };
-            }
-
-            return Promise.resolve({
-                advanced: advanced,
-            });
+        if (model.get('accountId')) {
+            accountId = model.get('accountId');
+            accountName = model.get('accountName');
         }
+
+        if (!accountId && model.get('parentType') === 'Account' && model.get('parentId')) {
+            accountId = model.get('parentId');
+            accountName = model.get('parentName');
+        }
+
+        if (accountId) {
+            advanced.account = {
+                attribute: 'accountId',
+                type: 'equals',
+                value: accountId,
+                data: {
+                    type: 'is',
+                    nameValue: accountName,
+                },
+            };
+        }
+
+        return Promise.resolve({
+            advanced: advanced,
+        });
     }
-});
+}
+
+export default SameAccountSelectRelatedHandler;
diff --git a/client/src/helpers/misc/field-language.js b/client/src/helpers/misc/field-language.js
index 857a3bb7e9..abbd3a5919 100644
--- a/client/src/helpers/misc/field-language.js
+++ b/client/src/helpers/misc/field-language.js
@@ -30,26 +30,26 @@
 
 /**
  * A field-language util.
- *
- * @class
- * @param {module:metadata} metadata A metadata.
- * @param {module:language} language A language.
  */
-const FieldLanguage = function (metadata, language) {
-    /**
-     * @private
-     * @type {module:metadata}
-     */
-    this.metadata = metadata;
+class FieldLanguage {
 
     /**
-     * @private
-     * @type {module:language}
+     * @param {module:metadata} metadata A metadata.
+     * @param {module:language} language A language.
      */
-    this.language = language;
-};
+    constructor(metadata, language) {
+        /**
+         * @private
+         * @type {module:metadata}
+         */
+        this.metadata = metadata;
 
-_.extend(FieldLanguage.prototype, /** @lends FieldLanguage# */{
+        /**
+         * @private
+         * @type {module:language}
+         */
+        this.language = language;
+    }
 
     /**
      * Translate an attribute.
@@ -58,61 +58,61 @@ _.extend(FieldLanguage.prototype, /** @lends FieldLanguage# */{
      * @param {string} name An attribute name.
      * @returns {string}
      */
-    translateAttribute: function (scope, name) {
+    translateAttribute(scope, name) {
         let label = this.language.translate(name, 'fields', scope);
 
         if (name.indexOf('Id') === name.length - 2) {
-            let baseField = name.substr(0, name.length - 2);
+            let baseField = name.slice(0, name.length - 2);
 
             if (this.metadata.get(['entityDefs', scope, 'fields', baseField])) {
                 label = this.language.translate(baseField, 'fields', scope) +
-                ' (' + this.language.translate('id', 'fields') + ')';
+                    ' (' + this.language.translate('id', 'fields') + ')';
             }
         }
         else if (name.indexOf('Name') === name.length - 4) {
-            let baseField = name.substr(0, name.length - 4);
+            let baseField = name.slice(0, name.length - 4);
 
             if (this.metadata.get(['entityDefs', scope, 'fields', baseField])) {
                 label = this.language.translate(baseField, 'fields', scope) +
-                ' (' + this.language.translate('name', 'fields') + ')';
+                    ' (' + this.language.translate('name', 'fields') + ')';
             }
         }
         else if (name.indexOf('Type') === name.length - 4) {
-            let baseField = name.substr(0, name.length - 4);
+            let baseField = name.slice(0, name.length - 4);
 
             if (this.metadata.get(['entityDefs', scope, 'fields', baseField])) {
                 label = this.language.translate(baseField, 'fields', scope) +
-                ' (' + this.language.translate('type', 'fields') + ')';
+                    ' (' + this.language.translate('type', 'fields') + ')';
             }
         }
 
         if (name.indexOf('Ids') === name.length - 3) {
-            let baseField = name.substr(0, name.length - 3);
+            let baseField = name.slice(0, name.length - 3);
 
             if (this.metadata.get(['entityDefs', scope, 'fields', baseField])) {
                 label = this.language.translate(baseField, 'fields', scope) +
-                ' (' + this.language.translate('ids', 'fields') + ')';
+                    ' (' + this.language.translate('ids', 'fields') + ')';
             }
         }
         else if (name.indexOf('Names') === name.length - 5) {
-            let baseField = name.substr(0, name.length - 5);
+            let baseField = name.slice(0, name.length - 5);
 
             if (this.metadata.get(['entityDefs', scope, 'fields', baseField])) {
                 label = this.language.translate(baseField, 'fields', scope) +
-                ' (' + this.language.translate('names', 'fields') + ')';
+                    ' (' + this.language.translate('names', 'fields') + ')';
             }
         }
         else if (name.indexOf('Types') === name.length - 5) {
-            let baseField = name.substr(0, name.length - 5);
+            let baseField = name.slice(0, name.length - 5);
 
             if (this.metadata.get(['entityDefs', scope, 'fields', baseField])) {
                 label = this.language.translate(baseField, 'fields', scope) +
-                ' (' + this.language.translate('types', 'fields') + ')';
+                    ' (' + this.language.translate('types', 'fields') + ')';
             }
         }
 
         return label;
-    },
-});
+    }
+}
 
 export default FieldLanguage;