add copyDynamicProperties

HLWeil · HLWeil · commit 8f6958f859ce · 2024-08-29T16:05:54.000+02:00
diff --git a/src/DynamicObj/DynamicObj.fs b/src/DynamicObj/DynamicObj.fs
@@ -23,7 +23,6 @@ type DynamicObj() =
         // first check the Properties collection for member
         this.TryGetPropertyInfo(name)
         |> Option.map (fun pi -> pi.GetValue(this))
-
     
     member this.GetValue (name) =
         this.TryGetValue(name).Value
@@ -68,7 +67,7 @@ type DynamicObj() =
         match this.TryGetStaticPropertyInfo name with
         | Some pi -> Some pi
         | None -> this.TryGetDynamicPropertyInfo name
-        
+
     /// Sets property value, creating a new property if none exists
     member this.SetValue (name,value) = // private
         // first check to see if there's a native property to set
@@ -99,7 +98,6 @@ type DynamicObj() =
         | Some _ -> failwith $"Cannot remove value for static, immutable property \"{name}\""
         | None -> ()
 
-
     member this.GetPropertyHelpers (includeInstanceProperties) =
         #if FABLE_COMPILER_JAVASCRIPT || FABLE_COMPILER_TYPESCRIPT           
         FableJS.getPropertyHelpers this
@@ -166,6 +164,23 @@ type DynamicObj() =
         #endif
         |> Seq.filter (fun kv -> kv.Key.ToLower() <> "properties")
 
+    /// Copies all dynamic members of the DynamicObj to the target DynamicObj.
+    member this.CopyDynamicPropertiesTo(target:#DynamicObj, ?overWrite) =
+        let overWrite = Option.defaultValue false overWrite
+        this.GetProperties(false)
+        |> Seq.iter (fun kv ->
+            match target.TryGetPropertyInfo kv.Key with
+            | Some pi when overWrite -> pi.SetValue target kv.Value
+            | Some _ -> failwith $"Property \"{kv.Key}\" already exists on target object and overWrite was not set to true."
+            | None -> target.SetValue(kv.Key,kv.Value)
+        )
+
+    /// Returns a new DynamicObj with only the dynamic properties of the original DynamicObj (sans instance properties).
+    member this.CopyDynamicProperties() =
+        let target = DynamicObj()
+        this.CopyDynamicPropertiesTo(target)
+        target
+
     member this.GetPropertyNames(includeInstanceProperties) =
         this.GetProperties(includeInstanceProperties)
         |> Seq.map (fun kv -> kv.Key)
diff --git a/tests/DynamicObject.Tests/DynamicObj.fs b/tests/DynamicObject.Tests/DynamicObj.fs
@@ -269,9 +269,44 @@ let tests_print = testList "Print" [
         Expect.isTrue print "Print failed for issue 14"
 ]
 
+let tests_copyDynamicProperties = testList "CopyDynamicProperties" [
+    testCase "NewObject" <| fun _ ->
+        let a = DynamicObj()
+        a.SetValue("a", 1)
+        a.SetValue("b", 2)
+        let b = a.CopyDynamicProperties()
+        Expect.equal a b "Values should be equal"
+    testCase "ExistingObject" <| fun _ ->
+        let a = DynamicObj()
+        a.SetValue("a", 1)
+        a.SetValue("b", 2)
+        let b = DynamicObj()
+        b.SetValue("c", 3)
+        a.CopyDynamicPropertiesTo(b)
+        Expect.equal (b.GetValue("a")) 1 "Value a should be copied"
+        Expect.equal (b.GetValue("b")) 2 "Value b should be copied"
+        Expect.equal (b.GetValue("c")) 3 "Value c should be unaffected"
+    testCase "NoOverwrite throws" <| fun _ ->
+        let a = DynamicObj()
+        a.SetValue("a", 1)
+        let b = DynamicObj()
+        b.SetValue("a", 3)
+        let f = fun () -> a.CopyDynamicPropertiesTo(b)
+        Expect.throws f "Should throw because property exists"
+    testCase "Overwrite" <| fun _ ->
+        let a = DynamicObj()
+        a.SetValue("a", 1)
+        let b = DynamicObj()
+        b.SetValue("a", 3)
+        Expect.notEqual a b "Values should not be equal before copying"
+        a.CopyDynamicPropertiesTo(b, true)
+        Expect.equal a b "Values should be equal"
+]
+
 let main = testList "DynamicObj" [
     tests_set
     tests_remove
     tests_formatString
     tests_combine
+    tests_copyDynamicProperties
 ]
