Revert back to eval in wasm InvokeJS with modularization support .

Wrap code to evaluate in a function with MONO, BINDING, INTERNAL
and module as local variables.

Added tests for running js expressions.

Co-authored-by: Pavel Savara <pavelsavara@microsoft.com>

src/libraries/System.Private.Runtime.InteropServices.JavaScript/tests/System/Runtime/InteropServices/JavaScript/MarshalTests.cs

@@ -871,5 +871,19 @@ public static void InternedStringReturnValuesWork()
             Assert.Equal("s: 1 length: 1", HelperMarshal._stringResource);
             Assert.Equal("1", HelperMarshal._stringResource2);
         }
+
+        [Fact]
+        public static void InvokeJSExpression()
+        {
+            var result = Runtime.InvokeJS(@"1 + 2");
+            Assert.Equal("3", result);
+        }
+
+        [Fact]
+        public static void InvokeJSNullExpression()
+        {
+            var result = Runtime.InvokeJS(@"null");
+            Assert.Null(result);
+        }
     }
 }

src/mono/wasm/runtime/method-calls.ts

@@ -541,18 +541,18 @@ export function mono_wasm_invoke_js(code: MonoString, is_exception: Int32Ptr): M
     if (code === MonoStringNull)
         return MonoStringNull;
 
-    const js_code = conv_string(code);
+    const js_code = conv_string(code)!;
 
     try {
-        const closure = {
-            Module, MONO, BINDING, INTERNAL
+        const closedEval = function (Module: EmscriptenModule, MONO: any, BINDING: any, INTERNAL: any, code: string) {
+            return eval(code);
         };
-        const fn_body_template = `const {Module, MONO, BINDING, INTERNAL} = __closure; const __fn = function(){ ${js_code} }; return __fn.call(__closure);`;
-        const fn_defn = new Function("__closure", fn_body_template);
-        const res = fn_defn(closure);
+        let res = closedEval(Module, MONO, BINDING, INTERNAL, js_code);
         Module.setValue(is_exception, 0, "i32");
         if (typeof res === "undefined" || res === null)
             return MonoStringNull;
+
+        res = res.toString();
         if (typeof res !== "string")
             return wrap_error(is_exception, `Return type of InvokeJS is string. Can't marshal response of type ${typeof res}.`);
         return js_string_to_mono_string(res);