code refactoring

Author: pchalamet

src/FSharp.MongoDB.Bson/Serialization/Conventions/FSharpRecordConvention.fs

@@ -27,8 +27,6 @@ open System.Reflection
 type FSharpRecordConvention() =
     inherit ConventionBase()
 
-    static let nrtContext = NullabilityInfoContext()
-
     interface IClassMapConvention with
         member _.Apply classMap =
             match classMap.ClassType with
@@ -41,9 +39,5 @@ type FSharpRecordConvention() =
                 classMap.MapConstructor(ctor, names) |> ignore
 
                 // Map each field of the record type.
-                fields |> Array.iter (fun pi ->
-                    let memberMap = classMap.MapMember(pi)
-                    let nrtInfo = nrtContext.Create(pi)
-                    if nrtInfo.WriteState = NullabilityState.Nullable then
-                        memberMap.SetDefaultValue(null).SetIsRequired(false) |> ignore)
+                fields |> Array.iter (mkMemberNullable classMap)
             | _ -> ()

src/FSharp.MongoDB.Bson/Serialization/Conventions/UnionCaseConvention.fs

@@ -30,8 +30,6 @@ open MongoDB.Bson.Serialization.Helpers
 type UnionCaseConvention() =
     inherit ConventionBase()
 
-    static let nrtContext = NullabilityInfoContext()
-
     let tryGetUnionCase (typ:System.Type) =
         // 8.5.4. Compiled Form of Union Types for Use from Other CLI Languages
         //   A compiled union type U has [o]ne CLI nested type U.C for each non-null union case C.
@@ -78,12 +76,7 @@ type UnionCaseConvention() =
         classMap.MapCreator(del, names) |> ignore
 
         // Map each field of the union case.
-        // Map each field of the record type.
-        fields |> Array.iter (fun pi ->
-            let memberMap = classMap.MapMember(pi)
-            let nrtInfo = nrtContext.Create(pi)
-            if nrtInfo.WriteState = NullabilityState.Nullable then
-                memberMap.SetDefaultValue(null).SetIsRequired(false) |> ignore)
+        fields |> Array.iter (mkMemberNullable classMap)
 
     interface IClassMapConvention with
         member _.Apply classMap =

src/FSharp.MongoDB.Bson/Serialization/FSharpTypeHelpers.fs

@@ -23,6 +23,8 @@ module private Helpers =
 
     let bindingFlags = BindingFlags.Public ||| BindingFlags.NonPublic
 
+    let nrtContext = NullabilityInfoContext()
+
     /// <summary>
     /// Returns <c>Some typ</c> when <c>pred typ</c> returns true, and <c>None</c> when
     /// <c>pred typ</c> returns false.
@@ -90,3 +92,9 @@ module private Helpers =
     /// Creates a generic type <c>'T</c> using the generic arguments of <c>typ</c>.
     /// </summary>
     let mkGenericUsingDef<'T> (typ:System.Type) = typ.GetGenericArguments() |> mkGeneric<'T>
+
+    let mkMemberNullable (memberMap: BsonClassMap) (propertyInfo: PropertyInfo) =
+        let memberMap = memberMap.MapMember(propertyInfo)
+        let nrtInfo = nrtContext.Create(propertyInfo)
+        if nrtInfo.WriteState = NullabilityState.Nullable then
+            memberMap.SetDefaultValue(null).SetIsRequired(false) |> ignore