Foreign key relations in arrays are not reactive

[dradovic]

Relations that are defined through arrays are not reactive. For example, in

Meteor.publish("groups", function(userId) {
  return Meteor.publishWithRelations({
    handle: this,
    collection: Groups,
    filter: {
      $or: [
        {
          ownerId: userId
        }, {
          memberIds: userId
        }
      ]
    },
    mappings: [
      {
        key: "memberIds",
        collection: Meteor.users
      }
    ]
  });
});

once loaded, the users collection on the client will not reflect changes in the group.memberIds array.

[svasva]

Thats true, it doesn't observe for foreign key changes. So it looks like a feature request :)

[lgandecki]

It doesn't? I thought that following code was doing just that.

 changed: (id, fields) ->
      _.each fields, (value, key) ->
        changedMappings = _.where(params.mappings, {key: key, reverse: false})
        doMapping(id, fields, changedMappings)

I've made some changes to be able to work with nested arrays of objects (I have a course object, and inside it I have a comments objects, that have userIds in it, so, like

Course = {
    name: something,
    comments: [
        {
            userId: firstUserId,
            comment: "some text"
        }
        {
            userId: secondUserId,
            comment: "different text"
        }
    ]
}

I needed to publish all the users that commented on the course. To make it work

@@ -20,7 +20,10 @@
         mapFilter[mapping.key] = id
       else
         objKey = mapping.key
-        mapFilter._id = obj[mapping.key]
+        if mapping.nestedArray
+            mapFilter._id = _.uniq(_.pluck(obj[mapping.nestedArray], mapping.key))
+        else
+            mapFilter._id = obj[mapping.key]
         if _.isArray(mapFilter._id)
           mapFilter._id = {$in: mapFilter._id}
       _.extend(mapFilter, mapping.filter)
@@ -47,7 +50,9 @@
       doMapping(id, fields, params.mappings)
     changed: (id, fields) ->
       _.each fields, (value, key) ->
-        changedMappings = _.where(params.mappings, {key: key, reverse: false})
+        changedKeyMappings = _.where(params.mappings, {key: key, reverse: false})
+        changedNestedArrayMappings = _.where(params.mappings, {nestedArray: key})
+        changedMappings = changedKeyMappings.concat changedNestedArrayMappings
         doMapping(id, fields, changedMappings)
       pub.changed(collection._name, id, fields)
     removed: (id) ->

Mappings:

mappings: [
    {
        key: "userId",
        nestedArray: "comments",
        collection: Meteor.users
    }
]

My point is - when someone comments on the course I automatically get his info published to my client, if the client is looking at the course comments at the time. I can't think of an collection in my db that would just use the array of ids so I can't double check it, but I'd expect it to work the same way.

[dradovic]

As far as I remember, my issue was rather that adding and removal of new IDs in the array were not reflected (rather than modifications of the existing records). Might be related to #7 (and ultimately to meteor/meteor#944) which was the reason I had to abandon this package anyway.

[jwaltz]

Igandecki, thank you for the code to make foreign keys in a nested array of objects work. I am using your changes currently. Was wondering if you've discovered anything new about this issue?