code: function( object, propertyTable, eid ) {
  
  		// Create a new BST for this entity for by-value matching
  		if (this.indexVal[eid] === undefined)
  			this.indexVal[eid] = new BinarySearchTree({
  				compareKeys: objectBstComparison,
  				checkValueEquality: objectBstEquals,
  				unique: true,
  			});
  
  		// Keep object references
  		var nid = this.indexRef.length;
  		this.indexVal[eid].insert( propertyTable, nid );
  		this.indexRef.push( object );
  
  		// Keep ID on the object itself so we have a faster lookup,
  		// and do it in a non-enumerable property so it doesn't pollute the objects.
  		Object.defineProperty(
  			object, "__iref__", {
  				enumerable: false,
  				value: nid,
  			}
  		);
  
  	}
docs: Keep the specified object in the lookup tables