Support Cetrek 2900 wind data (without defined Reference) (#255)

feature: treat undefined 130306 Reference as Apparent

Seen on a boat with a Digital Yacht WND100 feeding NMEA0183 into a
Cetrek 2900 which transmits NMEA2000. The WND100 declares its
measurements as Relative, but the Cetrek outputs 0xFF for the byte
contains the Reference.

Author: stefanor

pgns/130306.js

@@ -3,7 +3,7 @@ module.exports = [
     source: 'Wind Speed',
     node: 'environment.wind.speedApparent',
     filter: function (n2k) {
-      return n2k.fields['Reference'] === 'Apparent'
+      return n2k.fields['Reference'] === 'Apparent' || n2k.fields['Reference'] === undefined
     }
   },
   {
@@ -23,7 +23,7 @@ module.exports = [
   {
     node: 'environment.wind.angleApparent',
     filter: function (n2k) {
-      return n2k.fields['Reference'] === 'Apparent'
+      return n2k.fields['Reference'] === 'Apparent' || n2k.fields['Reference'] === undefined
     },
     value: function (n2k) {
       var angle = Number(n2k.fields['Wind Angle'])

test/130306_wind_data.js

@@ -98,4 +98,21 @@ describe('130306 Wind Data', function () {
     )
     tree.should.be.validSignalKVesselIgnoringIdentity
   })
+
+  it('Cetrek sentence converts', function () {
+    var tree = require('./testMapper').toNested(
+      JSON.parse(
+        '{"prio":5,"src":75,"dst":255,"pgn":130306,"timestamp":"2022-12-10T15:58:34.529Z","fields":{"Wind Speed":1.54,"Wind Angle":2.3545},"description":"Wind Data"}'
+      )
+    )
+    tree.should.have.nested.property(
+      'environment.wind.speedApparent.value',
+      1.54
+    )
+    tree.should.have.nested.property(
+      'environment.wind.angleApparent.value',
+      2.3545
+    )
+    tree.should.be.validSignalKVesselIgnoringIdentity
+  })
 })