Error "Uncaught TypeError: Cannot read property 'update' of undefined" when using firebase-document

[mm-gmbd]

This is mentioned in issue #31, but it looks like that issue has gone cold and the title is a little misleading, so I'm opening this issue for the following error:

Error "Uncaught TypeError: Cannot read property 'update' of undefined"

After performing a fresh clone of my project repository, I'm now receiving this issue. I was on firebase-element v1.0.10, and after the clone I'm on the latest v.1.0.12, but nothing in the change logs would seem to affect this behavior... regardless, I'm receiving the error.

I'm at a loss after some debugging... the code is as follows:

<firebase-document
  location="[[_computeUserLocation(location, _user)]]"
  data={{userData}}>
</firebase-document>

The property userData was originally set to an empty object in the element's properties:

properties: {
  ...,
  userData: {
    type: Object,
    value: function(){ return {} }
  }
}

But, removing the value, or removing the property entirely has no effect.

I've added the following logs to firebase-document:

_localDataChanged: function(change) {
  var pathFragments = change.path.split('.');

  console.log("change",change);
  console.log("this.location: ",this.location)
  console.log("this.query: ",this.query)

  if (pathFragments.length === 1) {
    // this._updateRemoteDocument();
    return;
  }

  this._setRemoteDocumentChild(
    pathFragments[1],
    change.base[pathFragments[1]]
  );
},

> change Object {path: "data", value: Object, base: Object } //both value and base are empty objects
> this.location: undefined
> this.query: undefined

The last line of output is the issue, because _updateRemoteDocument is defined as follows:

_updateRemoteDocument: function() {
  this._log('Updating remote document');
  this.query.update(this.dataAsObject); //query does not exist!!!
},

But, considering "query" is a property of firebase-document, I'm confused as to how it is simply undefined...

This raises another question for me as well, say I'd like to simply get data using firebase-document at a location that I have both read and write access to. With firebase-document, I provide a property to bind data to, but this always attempts to write to the location supplied first... how can just a pure read be accomplished??