fix(parser): convert dates to ISO-Strings

Return all dates (`start`, `end`, and `createdAt`) as ISO-Strings,
instead of Date objects to maintain consistency.

BREAKING CHANGE:

The dates were returned as a mix of ISO-Strings and Date Objects
in previous versions.

To migrate your project, confirm that you are handling the dates
received from scrapegoat correctly.

lib/xml/parser.js

@@ -82,7 +82,11 @@ function getNormalizedEndDate(endDate, duration) {
 
     // CalDav saves the end date of all day events as the start of the next day
     // To fix this, we subtract one second from the end date
-    return allDayEvent ? moment(endDate).subtract(1, "seconds").toISOString() : endDate;
+    return (
+        allDayEvent ?
+            new Date(moment(endDate).subtract(1, "seconds")) :
+            endDate
+    ).toISOString();
 }
 
 function getNormalOccurenceEventData(nextEvent, eventData, vevent) {
@@ -96,11 +100,11 @@ function getNormalOccurenceEventData(nextEvent, eventData, vevent) {
         uid,
         location,
         description,
-        start: new Date(dtstart),
+        start: new Date(dtstart).toISOString(),
         end: getNormalizedEndDate(new Date(dtend), duration),
         duration,
         type: { recurring: true, edited: false },
-        createdAt: new Date(vevent.getFirstPropertyValue("created"))
+        createdAt: new Date(vevent.getFirstPropertyValue("created")).toISOString()
     };
 }
 
@@ -114,11 +118,11 @@ function getModifiedOccurenceEventData(vevent, eventData) {
         uid: vevent.getFirstPropertyValue("uid"),
         location: vevent.getFirstPropertyValue("location"),
         description: vevent.getFirstPropertyValue("description"),
-        start: new Date(dtstart),
+        start: new Date(dtstart).toISOString(),
         end: getNormalizedEndDate(new Date(dtend), duration),
         duration,
         type: { recurring: true, edited: true },
-        createdAt: new Date(vevent.getFirstPropertyValue("created"))
+        createdAt: new Date(vevent.getFirstPropertyValue("created")).toISOString()
     };
 }
 
@@ -218,11 +222,11 @@ function parseEvents(xml) {
                     uid: vevent.getFirstPropertyValue("uid"),
                     location: vevent.getFirstPropertyValue("location"),
                     description: vevent.getFirstPropertyValue("description"),
-                    start: new Date(dtstart),
+                    start: new Date(dtstart).toISOString(),
                     end: getNormalizedEndDate(new Date(dtend), duration),
                     duration,
                     type: { recurring: false, edited: false },
-                    createdAt: new Date(vevent.getFirstPropertyValue("created"))
+                    createdAt: new Date(vevent.getFirstPropertyValue("created")).toISOString()
                 };
 
                 formatted.push({
@@ -234,8 +238,8 @@ function parseEvents(xml) {
         });
 
         formatted.sort((a, b) => {
-            const aStart = new ICAL.Time().fromJSDate(a.data.start);
-            const bStart = new ICAL.Time().fromJSDate(b.data.start);
+            const aStart = new ICAL.Time().fromJSDate(new Date(a.data.start));
+            const bStart = new ICAL.Time().fromJSDate(new Date(b.data.start));
 
             return aStart.compare(bStart);
         });