Enable IJSObjectReference to handle null/undefined values

Author: rolandVi

src/JSInterop/Microsoft.JSInterop.JS/src/src/Microsoft.JSInterop.ts

@@ -155,6 +155,12 @@ export module DotNet {
    * @throws Error if the given value is not an Object.
    */
   export function createJSObjectReference(jsObject: any): any {
+      if (jsObject === null || jsObject === undefined) {
+          return {
+              [jsObjectIdKey]: -1
+          };
+      }
+
       if (jsObject && (typeof jsObject === "object" || jsObject instanceof Function)) {
           cachedJSObjectsById[nextJsObjectId] = new JSObject(jsObject);
 
@@ -220,7 +226,7 @@ export module DotNet {
   export function disposeJSObjectReference(jsObjectReference: any): void {
       const id = jsObjectReference && jsObjectReference[jsObjectIdKey];
 
-      if (typeof id === "number") {
+      if (typeof id === "number" && id !== -1) {
           disposeJSObjectReferenceById(id);
       }
   }
@@ -573,7 +579,7 @@ export module DotNet {
   }
 
   /** Traverses the object hierarchy to find an object member specified by the identifier.
-   * 
+   *
    * @param obj Root object to search in.
    * @param identifier Complete identifier of the member to find, e.g. "document.location.href".
    * @returns A tuple containing the immediate parent of the member and the member name.
@@ -586,19 +592,19 @@ export module DotNet {
       // Error handling in case of undefined last key depends on the type of operation.
       for (let i = 0; i < keys.length - 1; i++) {
           const key = keys[i];
-  
+
           if (current && typeof current === 'object' && key in current) {
               current = current[key];
           } else {
               throw new Error(`Could not find '${identifier}' ('${key}' was undefined).`);
           }
       }
-  
+
       return [current, keys[keys.length - 1]];
   }
 
   /** Takes an object member and a call type and returns a function that performs the operation specified by the call type on the member.
-   * 
+   *
    * @param parent Immediate parent of the accessed object member.
    * @param memberName Name (key) of the accessed member.
    * @param callType The type of the operation to perform on the member.
@@ -640,50 +646,50 @@ export module DotNet {
       if (!(propName in obj)) {
           return false;
       }
-  
+
       // If the property is present we examine its descriptor, potentially needing to walk up the prototype chain.
       while (obj !== undefined) {
           const descriptor = Object.getOwnPropertyDescriptor(obj, propName);
-  
+
           if (descriptor) {
               // Return true for data property
               if (descriptor.hasOwnProperty('value')) {
                   return true
               }
-          
+
               // Return true for accessor property with defined getter.
               return descriptor.hasOwnProperty('get') && typeof descriptor.get === 'function';
           }
-  
+
           obj = Object.getPrototypeOf(obj);
       }
-  
+
       return false;
   }
-  
+
   function isWritableProperty(obj: any, propName: string) {
       // Return true for missing property if the property can be added.
       if (!(propName in obj)) {
           return Object.isExtensible(obj);
       }
-  
+
       // If the property is present we examine its descriptor, potentially needing to walk up the prototype chain.
       while (obj !== undefined) {
           const descriptor = Object.getOwnPropertyDescriptor(obj, propName);
-  
+
           if (descriptor) {
               // Return true for writable data property.
               if (descriptor.hasOwnProperty('value') && descriptor.writable) {
                   return true;
               }
-              
+
               // Return true for accessor property with defined setter.
               return descriptor.hasOwnProperty('set') && typeof descriptor.set === 'function';
           }
-  
+
           obj = Object.getPrototypeOf(obj);
       }
-  
+
       return false;
   }
 

src/JSInterop/Microsoft.JSInterop.JS/src/test/CallDispatcher.test.ts

@@ -395,4 +395,25 @@ describe("CallDispatcher", () => {
 
         expect(result2).toBe("30");
     });
-});
+
+    test("createJSObjectReference: Handles null values without throwing", () => {
+        const nullRef = DotNet.createJSObjectReference(null);
+        expect(nullRef).toEqual({ [jsObjectId]: -1 });
+    });
+
+    test("createJSObjectReference: Handles undefined values without throwing", () => {
+        const undefinedRef = DotNet.createJSObjectReference(undefined);
+        expect(undefinedRef).toEqual({ [jsObjectId]: -1 });
+    });
+
+    test("disposeJSObjectReference: Safely handles null reference disposal", () => {
+        const nullRef = DotNet.createJSObjectReference(null);
+        expect(() => DotNet.disposeJSObjectReference(nullRef)).not.toThrow();
+    });
+
+    test("createJSObjectReference: Still throws for invalid types", () => {
+        expect(() => DotNet.createJSObjectReference("string")).toThrow();
+        expect(() => DotNet.createJSObjectReference(123)).toThrow();
+        expect(() => DotNet.createJSObjectReference(true)).toThrow();
+    });
+});

src/JSInterop/Microsoft.JSInterop/src/Infrastructure/JSObjectReferenceJsonConverter.cs

@@ -22,6 +22,12 @@ public override bool CanConvert(Type typeToConvert)
     public override IJSObjectReference? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
         var id = JSObjectReferenceJsonWorker.ReadJSObjectReferenceIdentifier(ref reader);
+
+        if (id == -1)
+        {
+            return null;
+        }
+
         return new JSObjectReference(_jsRuntime, id);
     }
 

src/JSInterop/Microsoft.JSInterop/test/Infrastructure/JSObjectReferenceJsonConverterTest.cs

@@ -87,4 +87,17 @@ public void Write_WritesValidJson()
         // Assert
         Assert.Equal($"{{\"__jsObjectId\":{jsObjectRef.Id}}}", json);
     }
+
+    [Fact]
+    public void Read_ReturnsNull_WhenJSObjectIdIsMinusOne()
+    {
+        // Arrange
+        var json = "{\"__jsObjectId\":-1}";
+
+        // Act
+        var deserialized = JsonSerializer.Deserialize<IJSObjectReference>(json, JsonSerializerOptions);
+
+        // Assert
+        Assert.Null(deserialized);
+    }
 }