Use parseIntSafe and some minor fixes

codecs/ZDA.ts

@@ -1,42 +1,42 @@
 /*
- * === GST - UTC day, month, and year, and local time zone offset ===
+ * === ZDA - Time & Date - UTC, day, month, year and local time zone ===
  *
  * ------------------------------------------------------------------------------
- *        1         2  3  4    5  6   7
- *        |         |  |  |    |  |   |
- * $--GST,hhmmss.ss,dd,mm,yyyy,zz,zz,*hh<CR><LF>
+ *	      1         2  3  4    5  6  7
+ *        |         |  |  |    |  |  |
+ * $--ZDA,hhmmss.ss,dd,mm,yyyy,zz,zz*hh<CR><LF>
  * ------------------------------------------------------------------------------
  *
  * Field Number:
- * 1. UTC time
- * 2. Day, ranging between 01 and 31
- * 3. Month, ranging between 01 and 12
- * 4. Year
- * 5. Local time zone offset from GMT, ranging from 00 through ±13 hours
- * 6. Local time zone offset from GMT, ranging from 00 through 59 minutes
+ * 1. UTC time (hours, minutes, seconds, may have fractional subsecond)
+ * 2. Day, 01 to 31
+ * 3. Month, 01 to 12
+ * 4. Year (4 digits)
+ * 5. Local zone description, 00 to +- 13 hours
+ * 6. Local zone minutes description, 00 to 59, apply same sign as local hours
  * 7. Checksum
  */
 
-import { parseTime } from "../helpers";
+import { parseIntSafe, parseTime } from "../helpers";
 
 export const sentenceId: "ZDA" = "ZDA";
-export const sentenceName = "Data and Time";
+export const sentenceName = "UTC, day, month, year, and local time zone";
 
 export interface ZDAPacket {
     sentenceId: "ZDA";
     sentenceName: string;
     talkerId?: string;
     datetime: Date;
-    localHoursOffset: number;
-    localMinutesOffset: number;
+    localZoneHours: number;
+    localZoneMinutes: number;
 }
 
 export function decodeSentence(fields: string[]): ZDAPacket {
     return {
         sentenceId: sentenceId,
         sentenceName: sentenceName,
         datetime: parseTime(fields[1], fields.slice(2, 5).join("")),
-        localHoursOffset: parseInt(fields[5], 10),
-        localMinutesOffset: parseInt(fields[6], 10)
+        localZoneHours: parseIntSafe(fields[5]),
+        localZoneMinutes: parseIntSafe(fields[6])
     };
 }

tests/ZDAtest.ts

@@ -4,14 +4,11 @@ import { parseNmeaSentence } from "../index";
 
 describe("ZDA", (): void => {
     it("parser", (): void => {
-        const packet = parseNmeaSentence(
-            "$GNZDA,050956.00,30,03,2020,00,00*77"
-        );
-
+        const packet = parseNmeaSentence("$GPZDA,160012.71,11,03,2004,-1,00*7D");
         packet.should.have.property("sentenceId", "ZDA");
-        packet.should.have.property("sentenceName", "Data and Time");
-        packet.should.have.property("datetime", new Date("2020-03-30T05:09:56.000Z"));
-        packet.should.have.property("localHoursOffset", 0);
-        packet.should.have.property("localMinutesOffset", 0);
+        packet.should.have.property("sentenceName", "UTC, day, month, year, and local time zone");
+        packet.should.have.property("datetime", new Date("2004-03-11T16:00:12.710Z"));
+        packet.should.have.property("localZoneHours", -1);
+        packet.should.have.property("localZoneMinutes", 0);
     });
 });