normalize my dates

src/weather-dashboard.ts

@@ -15,7 +15,7 @@ export default class WeatherDashboard {
     return this.cities.map((city) => ({
       name: city.label,
       data: city.data
-        .map((d) => ({ x: d.datetime, y: d.temperature }))
+        .map((d) => ({ x: normalizeDate(d.datetime), y: d.temperature }))
         .slice(0, this.forecastDays),
     }));
   }
@@ -88,6 +88,12 @@ export default class WeatherDashboard {
     });
   }
 }
+// truncates the datetimes to just a date, so it's easy to compare cities in different timezones
+export function normalizeDate(datetime: Date) {
+  const month = datetime.getMonth() + 1
+  const day = datetime.getDate()
+  return new Date(`${datetime.getFullYear()}-${month}-${day}`);
+}
 
 export function formatDate(datetime: Date) {
   const month = String(datetime.getMonth() + 1).padStart(2, '0');