UI: Handle histograms without buckets

Signed-off-by: beorn7 <beorn@grafana.com>

web/ui/react-app/src/pages/graph/DataTable.tsx

@@ -169,10 +169,12 @@ export const HistogramString: FC<HistogramStringProps> = ({ h }) => {
   }
   const buckets: string[] = [];
 
-  for (const bucket of h.buckets) {
-    const left = bucket[0] === 3 || bucket[0] === 1 ? '[' : '(';
-    const right = bucket[0] === 3 || bucket[0] === 0 ? ']' : ')';
-    buckets.push(left + bucket[1] + ',' + bucket[2] + right + ':' + bucket[3] + ' ');
+  if (h.buckets) {
+    for (const bucket of h.buckets) {
+      const left = bucket[0] === 3 || bucket[0] === 1 ? '[' : '(';
+      const right = bucket[0] === 3 || bucket[0] === 0 ? ']' : ')';
+      buckets.push(left + bucket[1] + ',' + bucket[2] + right + ':' + bucket[3] + ' ');
+    }
   }
 
   return (

web/ui/react-app/src/types/types.ts

@@ -7,7 +7,7 @@ export interface Metric {
 export interface Histogram {
   count: string;
   sum: string;
-  buckets: [number, string, string, string][];
+  buckets?: [number, string, string, string][];
 }
 
 export interface Exemplar {