feat(126983): expose alert location text in notification value (#330)

PGN 126985 (Alert Text) carries two strings: the alert description and
an optional location description (alertLocationTextDescription). The
126985 handler already caches both, but the 126983 (Alert) handler only
read textDescription back out, so the location was silently dropped from
the SignalK notification even though the device sends it.

Add a `location` field to the notification value, sourced from the
cached locationTextDescription and defaulting to '' when absent.

Author: dirkwa

pgns/126983.js

@@ -70,6 +70,7 @@ module.exports = [
         state: resolved.sk,
         method: ['visual', 'sound'],
         message: state.alerts[alertId].textDescription,
+        location: state.alerts[alertId].locationTextDescription || '',
         alertType: n2k.fields.alertType,
         alertCategory: n2k.fields.alertCategory,
         alertSystem: n2k.fields.alertSystem,

test/126983_alert.js

@@ -12,7 +12,7 @@ var state = {
     alerts: {
       '23480': {
         languageId: 'English (US)',
-        locationTextDescription: '',
+        locationTextDescription: 'Engine Room',
         textDescription: 'TEST: Temperature over 0'
       }
     }
@@ -23,6 +23,7 @@ var value = {
   state: 'warn',
   method: ['visual', 'sound'],
   message: 'TEST: Temperature over 0',
+  location: 'Engine Room',
   alertType: 'Warning',
   alertCategory: 'Navigational',
   alertSystem: 20,
@@ -153,4 +154,27 @@ describe('126983 Alert', function () {
       else process.env.NO_CANBOATJS = saved
     }
   })
+
+  it('defaults location to empty string when no location text is present', function () {
+    var noLocationState = {
+      '40': {
+        alerts: {
+          '23480': {
+            languageId: 'English (US)',
+            locationTextDescription: '',
+            textDescription: 'TEST: Temperature over 0'
+          }
+        }
+      }
+    }
+
+    var msg = JSON.parse(
+      '{"canId":166725416,"prio":2,"src":40,"dst":255,"pgn":126983,"direction":"R","time":"15:48:36.090","fields":{"Alert Type":"Warning","Alert Category":"Navigational","Alert System":20,"Alert ID":23480,"Data Source Network ID NAME":6458553273545042000,"Data Source Instance":0,"Data Source Index-Source":0,"Alert Occurrence Number":1,"Temporary Silence Status":"Not Temporary Silence","Acknowledge Status":"Not Acknowledged","Escalation Status":"Not Escalated","Temporary Silence Support":"Yes","Acknowledge Support":"Yes","Escalation Support":"Not Supported","Acknowledge Source Network ID NAME":1233993542451364400,"Trigger Condition":"Auto","Threshold Status":"Threshold Exceeded","Alert Priority":187,"Alert State":"Active"},"description":"Alert","timestamp":"2020-03-03T15:48:36.494Z"}'
+    )
+    var tree = mapper.toNested(msg, noLocationState)
+
+    tree.notifications.nmea.warning.navigational[20][23480].value.location.should.equal(
+      ''
+    )
+  })
 })