Mavgen JS: Heartbeat message mavlink_version should be automatic

Remove from constructor parameter list, and assign directly.
Remains settable by the unpacker for received messages.
Heartbeat test cases updated to reflect new interface.

generator/javascript/test/message10.js

@@ -93,13 +93,12 @@ describe('Complete MAVLink 1.0 packet', function() {
             , base_mode=45
             , custom_mode=68
             , system_status=13
-            , mavlink_version=1
         );
 
         this.mav.seq = 7;
 
         // Create a buffer that matches what the Python version of MAVLink creates
-        var reference = new Buffer.from([0xfe, 0x09, 0x07, 0x2a, 0x96, 0x00, 0x44, 0x00, 0x00, 0x00, 0x05, 0x03, 0x2d, 0x0d, 0x01, 0xac, 0x9d]);
+        var reference = new Buffer.from([0xfe, 0x09, 0x07, 0x2a, 0x96, 0x00, 0x44, 0x00, 0x00, 0x00, 0x05, 0x03, 0x2d, 0x0d, 0x03, 0x1c, 0xae]);
         new Buffer.from(heartbeat.pack(this.mav)).should.eql(reference);
 
     });
@@ -161,7 +160,6 @@ describe('MAVLink 1.0 message', function() {
             0, // base mode, mavlink10.MAV_MODE_FLAG_***
             0, // custom mode
             mavlink10.MAV_STATE_STANDBY, // system status
-            3 // MAVLink version
         );
 
         this.mav = new MAVLink10Processor();

generator/javascript/test/message20.js

@@ -97,7 +97,6 @@ describe('Complete MAVLink 2.0 packet', function() {
             , base_mode=45
             , custom_mode=68
             , system_status=13
-            , mavlink_version=3 // it's NOT a v1 vs v2 thing here. 3 really is its normal value.
         );
 
         this.mav.seq = 7;
@@ -356,7 +355,6 @@ describe('MAVLink 2.0 message', function() {
             0, // base mode, mavlink.MAV_MODE_FLAG_***
             0, // custom mode
             mavlink20.MAV_STATE_STANDBY, // system status
-            3 // MAVLink version
         );
 
         this.mav = new MAVLink20Processor();

generator/mavgen_javascript.py

@@ -257,18 +257,22 @@ def generate_classes(outf, msgs, xml):
     def field_descriptions(fields):
         ret = ""
         for f in fields:
-            ret += "                %-18s        : %s (%s)\n" % (f.name, f.description.strip(), f.type)
+            if not f.omit_arg:
+                ret += "                %-18s        : %s (%s)\n" % (f.name, f.description.strip(), f.type)
         return ret
 
     # now do all the messages
     for m in msgs:
 
         # assemble some strings we'll use later in outputting ..
         comment = "%s\n\n%s" % (wrapper.fill(m.description.strip()), field_descriptions(m.fields))
-        selffieldnames = 'self, '
+        argfieldnames = []
+        conststr = ""
         for f in m.fields:
-            selffieldnames += '%s, ' % f.name
-        selffieldnames = selffieldnames[:-2]
+            if not f.omit_arg:
+                argfieldnames.append(f.name)
+            else:
+                conststr = conststr + "    this.%s = %s;\n" % (f.name, f.const_value)
 
         # instance field support copied from mavgen_python
         if m.instance_field is not None:
@@ -289,11 +293,11 @@ def field_descriptions(fields):
         outf.write("    %s.messages.%s = function(" % ( get_mavhead(xml), m.name.lower() ) )
         outf.write(" ...moreargs ) {\n")
         # passing the dynamic args into the correct attributes, we can call the constructor with or without the 'moreargs'
-        outf.write("     [ this.%s ] = moreargs;\n" % " , this.".join(m.fieldnames))
+        outf.write("    [ this.%s ] = moreargs;\n" % " , this.".join(argfieldnames))
+        outf.write(conststr)
 
         # body: set message type properties    
         outf.write("""
-
     this._format = '%s';
     this._id = %s.MAVLINK_MSG_ID_%s;
     this.order_map = %s;