diff --git a/dev/Sieve/Model/Abstract.js b/dev/Sieve/Model/Abstract.js
index 4df08e039..b34858a7d 100644
--- a/dev/Sieve/Model/Abstract.js
+++ b/dev/Sieve/Model/Abstract.js
@@ -46,14 +46,13 @@ export class AbstractModel {
 	onDestroy() {
 		/** dispose ko subscribables */
 		this.disposables.forEach(disposable => {
-			disposable && typeof disposable.dispose === 'function' && disposable.dispose();
+			typeof disposable?.dispose === 'function' && disposable.dispose();
 		});
 		/** clear object entries */
 //		forEachObjectEntry(this, (key, value) => {
 		forEachObjectValue(this, value => {
 			/** clear CollectionModel */
-			let arr = ko.isObservableArray(value) ? value() : value;
-			arr && arr.onDestroy && arr.onDestroy();
+			(ko.isObservableArray(value) ? value() : value)?.onDestroy?.();
 			/** destroy ko.observable/ko.computed? */
 //			dispose(value);
 			/** clear object value */
@@ -78,7 +77,7 @@ export class AbstractModel {
 	 */
 	static reviveFromJson(json) {
 		let obj = this.validJson(json) ? new this() : null;
-		obj && obj.revivePropertiesFromJson(json);
+		obj?.revivePropertiesFromJson(json);
 		return obj;
 	}
 
diff --git a/dev/Sieve/Model/Filter.js b/dev/Sieve/Model/Filter.js
index 220532fe7..e96bf717f 100644
--- a/dev/Sieve/Model/Filter.js
+++ b/dev/Sieve/Model/Filter.js
@@ -65,7 +65,7 @@ export class FilterModel extends AbstractModel {
 
 		const fGetRealFolderName = folderFullName => {
 //			const folder = getFolderFromCacheList(folderFullName);
-//			return folder ? folder.fullName.replace('.' === folder.delimiter ? /\./ : /[\\/]+/, ' / ') : folderFullName;
+//			return folder?.fullName.replace('.' === folder.delimiter ? /\./ : /[\\/]+/, ' / ') : folderFullName;
 			return folderFullName;
 		};
 
@@ -222,9 +222,9 @@ export class FilterModel extends AbstractModel {
 	static reviveFromJson(json) {
 		const filter = super.reviveFromJson(json);
 		if (filter) {
-			filter.id = filter.id ? '' + filter.id : '';
+			filter.id = '' + (filter.id || '');
 			filter.conditions(
-				json.Conditions ? json.Conditions.map(aData => FilterConditionModel.reviveFromJson(aData)).filter(v => v) : []
+				(json.Conditions || []).map(aData => FilterConditionModel.reviveFromJson(aData)).filter(v => v)
 			);
 			filter.actionKeep(0 != json.Keep);
 			filter.actionNoStop(0 == json.Stop);
diff --git a/dev/Sieve/Utils.js b/dev/Sieve/Utils.js
index 4002b9e15..7544db465 100644
--- a/dev/Sieve/Utils.js
+++ b/dev/Sieve/Utils.js
@@ -12,7 +12,7 @@ export const
 		data = ko.observableArray(data);
 		data.subscribe(changes =>
 			changes.forEach(item =>
-				'deleted' === item.status && null == item.moved && item.value.onDestroy && item.value.onDestroy()
+				'deleted' === item.status && null == item.moved && item.value.onDestroy?.()
 			)
 		, data, 'arrayChange');
 		return data;
@@ -22,7 +22,7 @@ export const
 	koComputable = fn => ko.computed(fn, {'pure':true}),
 
 	arrayToString = (arr, separator) =>
-		arr.map(item => item.toString ? item.toString() : item).join(separator),
+		arr.map(item => item.toString?.() || item).join(separator),
 /*
 	getNotificationMessage = code => {
 		let key = getKeyByValue(Notification, code);
diff --git a/dev/Sieve/View/Filter.js b/dev/Sieve/View/Filter.js
index 6c623a2e9..cf5a2a03a 100644
--- a/dev/Sieve/View/Filter.js
+++ b/dev/Sieve/View/Filter.js
@@ -87,7 +87,7 @@ export class FilterPopupView extends rl.pluginPopupView {
 			folderListOptionsBuilder(
 				[rl.settings.get('SieveAllowFileintoInbox') ? '' : 'INBOX'],
 				[['', '']],
-				item => item ? item.localName() : ''
+				item => item?.localName() || ''
 			)
 		);
 
diff --git a/dev/Sieve/View/Script.js b/dev/Sieve/View/Script.js
index 20dd4a325..9cd1a0663 100644
--- a/dev/Sieve/View/Script.js
+++ b/dev/Sieve/View/Script.js
@@ -80,7 +80,7 @@ export class SieveScriptPopupView extends rl.pluginPopupView {
 
 					if (iError) {
 						self.saveError(true);
-						self.errorText((data && data.ErrorMessageAdditional) || getNotification(iError));
+						self.errorText(data?.ErrorMessageAdditional || getNotification(iError));
 					} else {
 						script.exists() || scripts.push(script);
 						script.exists(true);
diff --git a/dev/sieve.js b/dev/sieve.js
index b64bcb094..fcae436f7 100644
--- a/dev/sieve.js
+++ b/dev/sieve.js
@@ -58,7 +58,7 @@ window.Sieve = {
 		Remote.request('FiltersScriptDelete',
 			(iError, data) => {
 				if (iError) {
-					setError((data && data.ErrorMessageAdditional) || getNotification(iError));
+					setError(data?.ErrorMessageAdditional || getNotification(iError));
 				} else {
 					scripts.remove(script);
 				}
@@ -73,7 +73,7 @@ window.Sieve = {
 		Remote.request('FiltersScriptActivate',
 			(iError, data) => {
 				if (iError) {
-					setError((data && data.ErrorMessageAdditional) || iError)
+					setError(data?.ErrorMessageAdditional || iError)
 				} else {
 					scripts.forEach(script => script.active(script.name() === name));
 				}