Almost there

webapp/src/ClimateChart.ts

@@ -47,6 +47,10 @@ class ClimateChart {
     private async getInitialDataBlob(): Promise<SnapshotRecords> {
         try {
             const data = await fetch(this.rootUrl + "/data?since=" + new Date((new Date().getTime() - this.minutesDisplayed * 60 * 1000)).toISOString());
+            const payload = await data.json();
+            if (payload.snapshots.length < 0) {
+                throw new Error("Bad response - no snapshots found!");
+            }
             return await data.json();
         }
         catch (e) {

webapp/src/main.ts

@@ -12,6 +12,7 @@ function createClimateChart() {
     const argsStart = pathname.search(/\?minute-span=/);
     if (argsStart !== -1) {
         const parsedMins = Number(pathname[12]);
+        console.log(parsedMins);
         if (!isNaN(parsedMins) && parsedMins > 0) {
             minutesDisplayed = parsedMins;
         }