Fix few null checks to make master green (#25965)

public/app/plugins/datasource/graphite/configuration/ConfigEditor.tsx

@@ -86,7 +86,7 @@ export class ConfigEditor extends PureComponent<Props> {
                   label="Rollup indicator"
                   labelClass={'width-10'}
                   tooltip="Shows up as an info icon in panel headers when data is aggregated"
-                  checked={options.jsonData.rollupIndicatorEnabled}
+                  checked={!!options.jsonData.rollupIndicatorEnabled}
                   onChange={onUpdateDatasourceJsonDataOptionChecked(this.props, 'rollupIndicatorEnabled')}
                 />
               </div>

public/app/plugins/datasource/loki/configuration/DebugSection.tsx

@@ -84,6 +84,7 @@ type DebugField = {
   value?: string;
   href?: string;
 };
+
 function makeDebugFields(derivedFields: DerivedFieldConfig[], debugText: string): DebugField[] {
   return derivedFields
     .filter(field => field.name && field.matcherRegex)
@@ -91,7 +92,7 @@ function makeDebugFields(derivedFields: DerivedFieldConfig[], debugText: string)
       try {
         const testMatch = debugText.match(field.matcherRegex);
         const value = testMatch && testMatch[1];
-        let link: LinkModel<Field>;
+        let link: LinkModel<Field> = null;
 
         if (field.url && value) {
           link = getFieldLinksForExplore(

public/app/plugins/datasource/loki/datasource.ts

@@ -518,7 +518,7 @@ export class LokiDatasource extends DataSourceApi<LokiQuery, LokiOptions> {
   }
 
   showContextToggle = (row?: LogRowModel) => {
-    return row.searchWords && row.searchWords.length > 0;
+    return row && row.searchWords && row.searchWords.length > 0;
   };
 
   throwUnless = (err: any, condition: boolean, target: LokiQuery) => {

public/app/plugins/panel/singlestat/module.ts

@@ -502,7 +502,7 @@ class SingleStatCtrl extends MetricsPanelCtrl {
     function addSparkline() {
       const data: ShowData = ctrl.data;
       const width = elem.width();
-      if (width < 30) {
+      if (width && width < 30) {
         // element has not gotten it's width yet
         // delay sparkline render
         setTimeout(addSparkline, 30);