UI: Added validation of the obtained value from the cell style function

@@ -35,7 +35,7 @@ import { DataKey, WidgetActionDescriptor, WidgetConfig } from '@shared/models/wi
 import { IWidgetSubscription } from '@core/api/widget-api.models';
 import { UtilsService } from '@core/services/utils.service';
 import { TranslateService } from '@ngx-translate/core';
-import { createLabelFromDatasource, deepClone, hashCode, isDefined, isNumber } from '@core/utils';
+import { createLabelFromDatasource, deepClone, hashCode, isDefined, isNumber, isObject } from '@core/utils';
 import cssjs from '@core/css/css';
 import { sortItems } from '@shared/models/page/page-link';
 import { Direction } from '@shared/models/page/sort-order';
@@ -598,8 +598,16 @@ export class AlarmsTableWidgetComponent extends PageComponent implements OnInit,
       if (styleInfo.useCellStyleFunction && styleInfo.cellStyleFunction) {
         try {
           style = styleInfo.cellStyleFunction(value);
+          if (!isObject(style)) {
+            throw new TypeError(`${style === null ? 'null' : typeof style} instead of style object`);
+          }
+          if (Array.isArray(style)) {
+            throw new TypeError(`Array instead of style object`);
+          }
         } catch (e) {
           style = {};
+          console.warn(`Cell style function for data key '${key.label}' in widget '${this.ctx.widgetTitle}' ` +
+            `returns '${e}'. Please check your cell style function.`);
         }
       } else {
         style = this.defaultStyle(key, value);

@@ -40,7 +40,7 @@ import {
 import { IWidgetSubscription } from '@core/api/widget-api.models';
 import { UtilsService } from '@core/services/utils.service';
 import { TranslateService } from '@ngx-translate/core';
-import { createLabelFromDatasource, deepClone, hashCode, isDefined, isNumber } from '@core/utils';
+import { createLabelFromDatasource, deepClone, hashCode, isDefined, isNumber, isObject } from '@core/utils';
 import cssjs from '@core/css/css';
 import { CollectionViewer, DataSource } from '@angular/cdk/collections';
 import { DataKeyType } from '@shared/models/telemetry/telemetry.models';
@@ -515,8 +515,16 @@ export class EntitiesTableWidgetComponent extends PageComponent implements OnIni
       if (styleInfo.useCellStyleFunction && styleInfo.cellStyleFunction) {
         try {
           style = styleInfo.cellStyleFunction(value);
+          if (!isObject(style)) {
+            throw new TypeError(`${style === null ? 'null' : typeof style} instead of style object`);
+          }
+          if (Array.isArray(style)) {
+            throw new TypeError(`Array instead of style object`);
+          }
         } catch (e) {
           style = {};
+          console.warn(`Cell style function for data key '${key.label}' in widget '${this.ctx.widgetTitle}' ` +
+            `returns '${e}'. Please check your cell style function.`);
         }
       } else {
         style = {};
@@ -538,7 +546,7 @@ export class EntitiesTableWidgetComponent extends PageComponent implements OnIni
         try {
           content = contentInfo.cellContentFunction(value, entity, this.ctx);
         } catch (e) {
-            content = '' + value;
+          content = '' + value;
         }
       } else {
         content = this.defaultContent(key, contentInfo, value);

@@ -40,7 +40,7 @@ import {
 } from '@shared/models/widget.models';
 import { UtilsService } from '@core/services/utils.service';
 import { TranslateService } from '@ngx-translate/core';
-import {hashCode, isDefined, isDefinedAndNotNull, isNumber} from '@core/utils';
+import { hashCode, isDefined, isNumber, isObject } from '@core/utils';
 import cssjs from '@core/css/css';
 import { PageLink } from '@shared/models/page/page-link';
 import { Direction, SortOrder, sortOrderFromString } from '@shared/models/page/sort-order';
@@ -385,8 +385,16 @@ export class TimeseriesTableWidgetComponent extends PageComponent implements OnI
       if (styleInfo.useCellStyleFunction && styleInfo.cellStyleFunction) {
         try {
           style = styleInfo.cellStyleFunction(value);
+          if (!isObject(style)) {
+            throw new TypeError(`${style === null ? 'null' : typeof style} instead of style object`);
+          }
+          if (Array.isArray(style)) {
+            throw new TypeError(`Array instead of style object`);
+          }
         } catch (e) {
           style = {};
+          console.warn(`Cell style function for data key '${source.header[index - 1].dataKey.label}' in widget ` +
+            `'${this.ctx.widgetConfig.title}' returns '${e}'. Please check your cell style function.`);
         }
       }
     }