Fix low coupling weight = 0 on when there are no declarations

Author: JohT

cypher/DependsOn_Relationship_Weights/Add_fine_grained_weights_for_Typescript_internal_module_dependencies.cypher

@@ -9,7 +9,6 @@
       ,target
       ,moduleDependency
       ,moduleDependency.cardinality AS targetModuleCardinality
-
 // Get optional external (e.g. type) declarations that the external module (target) provides and the source module uses
 OPTIONAL MATCH (source)-[elementDependency:DEPENDS_ON|EXPORTS]->(elementType:TS)<-[:EXPORTS]-(target)
   WITH source
@@ -40,13 +39,18 @@ OPTIONAL MATCH (source)-[abstractDependency:DEPENDS_ON|EXPORTS]->(abstractType:T
 // - "lowCouplingElement25PercentWeight" subtracts 75% of the weights for abstract types like Interfaces and Type aliases
 //   to compensate for their low coupling influence. Not included "high coupling" elements like Functions and Classes 
 //   remain in the weight as they were. The same applies for "lowCouplingElement10PercentWeight" but with in a stronger manner.
+//   If there are no declarations and therefore the elementTypeCardinality is zero then the original targetModuleCardinality is used.
  SET moduleDependency.declarationCount        = elementTypeCount
     ,moduleDependency.abstractTypeCount       = abstractTypeCount
     ,moduleDependency.abstractTypeCardinality = abstractTypeCardinality
-    ,moduleDependency.lowCouplingElement25PercentWeight = 
-        toInteger(elementTypeCardinality - round(abstractTypeCardinality * 0.75))
-    ,moduleDependency.lowCouplingElement10PercentWeight = 
-        toInteger(elementTypeCardinality - round(abstractTypeCardinality * 0.90))
+    ,moduleDependency.lowCouplingElement25PercentWeight = toInteger(
+        coalesce(nullif(elementTypeCardinality, 0), targetModuleCardinality) - 
+        round(abstractTypeCardinality * 0.75)
+     )
+    ,moduleDependency.lowCouplingElement10PercentWeight = toInteger(
+        coalesce(nullif(elementTypeCardinality, 0), targetModuleCardinality) - 
+        round(abstractTypeCardinality * 0.90)
+     )
 RETURN source.globalFqn    AS sourceName
       ,target.globalFqn    AS targetName
       ,elementTypeCount