Add test to more explicitly cover both 'params array' and 'generics'-style interop APIs

samples/MonoSanity/wwwroot/index.html

@@ -45,6 +45,16 @@
     </form>
   </fieldset>
 
+  <fieldset>
+    <legend>Call JS from .NET (no boxing)</legend>
+    <form id="callJsNoBoxing">
+      <input id="callJsNoBoxingNumberA" value="28" /> /
+      <input id="callJsNoBoxingNumberB" value="4" /> =
+      <input id="callJsNoBoxingResult" readonly />
+      <button type="submit" disabled>Go</button>
+    </form>
+  </fieldset>
+
   <p id="loadingIndicator">Loading...</p>
 
   <script src="loader.js"></script>
@@ -91,6 +101,14 @@
       el('callJsResult').value = result;
     };
 
+    el('callJsNoBoxing').onsubmit = function (evt) {
+      evt.preventDefault();
+      var a = parseInt(el('callJsNoBoxingNumberA').value);
+      var b = parseInt(el('callJsNoBoxingNumberB').value);
+      var result = invokeMonoMethod('MonoSanityClient', 'MonoSanityClient', 'Examples', 'CallJsNoBoxing', [a, b]);
+      el('callJsNoBoxingResult').value = result;
+    };
+
     function el(id) {
       return document.getElementById(id);
     }
@@ -115,6 +133,15 @@
         return result === null || result === undefined
           ? result // Pass through null/undefined so we can verify this is handled upstream
           : javaScriptStringToDotNetString(result.toString());
+      },
+
+      divideNumbersUnmarshalled: function (a, b) {
+        // In this example, neither the arguments nor return value are boxed
+        // -- we expect to receive and return numbers directly
+        if (b === 0) {
+          throw new Error('Division by zero');
+        }
+        return a / b;
       }
     };
   </script>

samples/MonoSanityClient/Examples.cs

@@ -31,7 +31,8 @@ namespace MonoSanityClient
 
         public static string EvaluateJavaScript(string expression)
         {
-            var result = Runtime.InvokeJS<string, object, object, string>(out var exceptionMessage, "evaluateJsExpression", expression, null, null);
+            // For tests that call this method, we'll exercise the 'InvokeJSArray' code path
+            var result = Runtime.InvokeJSArray<string>(out var exceptionMessage, "evaluateJsExpression", expression, null, null);
             if (exceptionMessage != null)
             {
                 return $".NET got exception: {exceptionMessage}";
@@ -39,5 +40,18 @@ namespace MonoSanityClient
 
             return $".NET received: {(result ?? "(NULL)")}";
         }
+
+        public static string CallJsNoBoxing(int numberA, int numberB)
+        {
+            // For tests that call this method, we'll exercise the 'InvokeJS' code path
+            // since that doesn't box the params
+            var result = Runtime.InvokeJS<int, int, object, int>(out var exceptionMessage, "divideNumbersUnmarshalled", numberA, numberB, null);
+            if (exceptionMessage != null)
+            {
+                return $".NET got exception: {exceptionMessage}";
+            }
+
+            return $".NET received: {result}";
+        }
     }
 }

src/Microsoft.Blazor.Browser/Interop/WebAssembly.Runtime.cs

@@ -14,6 +14,6 @@ namespace WebAssembly
         public static extern TRes InvokeJS<T0, T1, T2, TRes>(out string exception, string funcName, T0 arg0, T1 arg1, T2 arg2);
 
         [MethodImpl(MethodImplOptions.InternalCall)]
-        public static extern TRes InvokeJSArray<TRes>(out string exception, string funcName, object[] args);
+        public static extern TRes InvokeJSArray<TRes>(out string exception, string funcName, params object[] args);
     }
 }

test/Microsoft.Blazor.E2ETest/Tests/MonoSanityTest.cs

@@ -101,6 +101,30 @@ namespace Microsoft.Blazor.E2ETest.Tests
             Assert.Equal(".NET received: (NULL)", result);
         }
 
+        [Fact]
+        public void CanCallJsFunctionsWithoutBoxing()
+        {
+            Navigate("/", noReload: true);
+
+            SetValue(Browser, "callJsNoBoxingNumberA", "108");
+            SetValue(Browser, "callJsNoBoxingNumberB", "4");
+            Browser.FindElement(By.CssSelector("#callJsNoBoxing button")).Click();
+
+            Assert.Equal(".NET received: 27", GetValue(Browser, "callJsNoBoxingResult"));
+        }
+
+        [Fact]
+        public void CanCallJsFunctionsWithoutBoxingAndReceiveException()
+        {
+            Navigate("/", noReload: true);
+
+            SetValue(Browser, "callJsNoBoxingNumberA", "1");
+            SetValue(Browser, "callJsNoBoxingNumberB", "0");
+            Browser.FindElement(By.CssSelector("#callJsNoBoxing button")).Click();
+
+            Assert.StartsWith(".NET got exception: Division by zero", GetValue(Browser, "callJsNoBoxingResult"));
+        }
+
         private static string GetValue(IWebDriver webDriver, string elementId)
         {
             var element = webDriver.FindElement(By.Id(elementId));