Too stupid to get a simple plugin working

Hi everybody,

Although I am not completely new to JavaScript programming, I am new to the concept of OVMS plugins and read the documentation regarding it several times..

I also got the fog light example up and running on my unit. But I guess I am missing something obviously important (that is not 100% explained in the documentation?) while trying to build a very simple plugin on my own: I don't want any events or updates, but simply extend the dashboard by some additional metrics read just once when initializing the dashboard.

This is what I have created:

Web Plugin (HTML page)

<!--
  Web plugin for hook /dashboard:body.pre
    - adds additional vehicle metrics
-->

<div id="additionalData">
  <span>Auxiliary Battery Voltage: </span><span id="auxBatVoltage"></span><br>
  <span>Auxiliary Battery Current: </span><span id="auxBatCurrent"></span><br>
  <span>DC/DC Converter Power: </span><span id="dcConverterPower"></span><br>
  <span>Main Battery SOC: </span><span id="mainBatSoc"></span><br>
  <span>Odometer: </span><span id="odometer"></span><br>
  <span>Trip distance: </span><span id="trip"></span><br>
  <span>Tire Pressures: </span><span id="tirePressures"></span><br>
</div>

<script>
(function(){
  // Object containing additional data
  var additionalData = {
    auxBatVoltage: "0 V",
    "auxBatCurrent": "0 A",
    "dcConverterPower": "0 W",
    "mainBatSoc": "0.0 %",
    "odometer": "0.0 km",
    "trip": "0.0 km",
    "tirePressures": "0.0 bar"
  };
  
  // State & UI update:
  function update(data) {
    $.extend(true, additionalData, data);
    // update indicator:
    $('#auxBatVoltage').text(additionalData.auxBatVoltage + " V");
    $('#auxBatCurrent').text(additionalData.auxBatCurrent + " A");
    $('#dcConverterPower').text(additionalData.dcConverterPower + " W");
    $('#mainBatSoc').text(additionalData.mainBatSoc + " %");
    $('#odometer').text(additionalData.odometer + " km");
    $('#trip').text(additionalData.trip + " km");
    $('#tirePressures').text(additionalData.tirePressures + " kPa");
  }
  
  // Init & install:
  $('#main').one('load', function(ev) {
    loadcmd('script eval additionalVehicleData.getMetrics()').then(function(output) {
      update(JSON.parse(output));
    });
  });

})();
</script>

And here is the corresponding (server side) JavaScript:

Module Plugin (saved to /store/scripts/lib/additionalVehicleData.js)

// API method additionalData.getMetrics():
exports.getMetrics = function() {
  JSON.print({
    "auxBatVoltage": OvmsMetrics.AsFloat("v.b.12v.voltage"),
    "auxBatCurrent": OvmsMetrics.AsFloat("v.b.12v.current"),
    "dcConverterPower": OvmsMetrics.AsFloat("v.c.12v.power"),
    "mainBatSoc": OvmsMetrics.AsFloat("v.b.soc"),
    "odometer": OvmsMetrics.AsFloat("v.p.odometer"),
    "trip": OvmsMetrics.AsFloat("v.p.trip"),
    "tirePressures": OvmsMetrics.AsFloat("v.t.pressure")
  });
};

When I access the dashboard after activating the plugin, I get the following output:

What am I missing / doing wrong?

And by the way: Is there any way to get more debug information from the server-side backend? Running the JavaScript above in the web editor already results in the following error:

So it seems like it doesn't unterstand "backend-only" (so non-native JavaScript) commands. But how can I write and test more complex scripts / plugins if it already stumbles across such things and therefore won't even parse my code...?

I guess I am also missing something here because it seems impossible to me how anybody could write a reasonable plugin without any real debugging environment.

And finally I found out that I can't delete any file I did upload to this forum's "backend" which I find rather strange regarding the strict limit of 20 MB max per user account. Regarding the help instructions, there should be a corresponding option, but I have simply been unable to figure out which keyboard shortcuts allows me the remove a file from the list...