Comments

packages/labs/src/components/timezone-picker/timezoneMetadata.ts

@@ -21,19 +21,26 @@ export function getTimezoneMetadata(timezone: string, date: Date, useManualCalc:
     return calculateMetadata(timezone, zone, timestamp);
 }
 
-function getValidAbbreviation(abbreviation: string) {
-    return isValidAbbreviation(abbreviation) ? abbreviation : undefined;
+/**
+ * Ignore abbreviations that are simply offsets, i.e. "+14" instead of "PST"
+ * @param abbreviation
+ */
+function getNonOffsetAbbreviation(abbreviation: string) {
+    return isNonOffsetAbbreviation(abbreviation) ? abbreviation : undefined;
 }
 
-function isValidAbbreviation(abbreviation: string) {
+function isNonOffsetAbbreviation(abbreviation: string) {
     return abbreviation != null && abbreviation.length > 0 && abbreviation[0] !== "-" && abbreviation[0] !== "+";
 }
 
+/**
+ * Use moment-timezone to parse the timestamp and provide timezone metadata
+ */
 function getMetadataFromMoment(timezone: string, zone: moment.MomentZone, timestamp: number) {
     const zonedDate = moment.tz(timestamp, timezone);
     const offset = zonedDate.utcOffset();
     const offsetAsString = zonedDate.format("Z");
-    const abbreviation = getValidAbbreviation(zonedDate.zoneAbbr());
+    const abbreviation = getNonOffsetAbbreviation(zonedDate.zoneAbbr());
     return {
         abbreviation,
         offset,
@@ -43,10 +50,14 @@ function getMetadataFromMoment(timezone: string, zone: moment.MomentZone, timest
     };
 }
 
+/**
+ * Manually determine timezone metadata by skipping the timestamp parsing and following
+ * http://momentjs.com/timezone/docs/#/data-formats/unpacked-format/
+ */
 function getMetadataFromMomentManual(timezone: string, zone: moment.MomentZone, timestamp: number) {
     const { abbrs, offsets, population, untils } = zone;
     const index = findOffsetIndex(timestamp, untils);
-    const abbreviation = getValidAbbreviation(abbrs[index]);
+    const abbreviation = getNonOffsetAbbreviation(abbrs[index]);
     const offset = offsets[index] * -1;
     const offsetAsString = getOffsetAsString(offset);
     return {