Replaced most properties in creature variables with links

instead of storing the entire property twice

app/imports/api/engine/computation/writeComputation/writeScope.js

@@ -19,6 +19,12 @@ export default function writeScope(creatureId, computation) {
     // Mongo can't handle keys that start with a dollar sign
     if (key[0] === '$' || key[0] === '_') continue;
 
+    // Remove empty objects
+    if (Object.keys(scope[key]).length === 0) {
+      delete scope[key];
+      continue;
+    }
+
     // Remove large properties that aren't likely to be accessed
     delete scope[key].parent;
     delete scope[key].ancestors;
@@ -30,6 +36,11 @@ export default function writeScope(creatureId, computation) {
       }
     }
 
+    // If this is a creature property, replace the property with a link
+    if (scope[key]._id && scope[key].type) {
+      scope[key] = { _propId: scope[key]._id };
+    }
+
     // Only update changed fields
     if (!EJSON.equals(variables[key], scope[key])) {
       if (!$set) $set = {};