Fix module export for oscilloscope.js to enable proper Jest coverage (#5956)

Author: stutijain2006

js/widgets/__tests__/oscilloscope.test.js

@@ -88,11 +88,7 @@ function createMockWidgetWindow() {
     };
 }
 
-// Load the Oscilloscope class by reading the source and wrapping it
-// so the class is assigned to global (class declarations are block-scoped)
-const fs = require("fs");
-const path = require("path");
-const oscilloscopeSource = fs.readFileSync(path.resolve(__dirname, "../oscilloscope.js"), "utf-8");
+const Oscilloscope = require("../oscilloscope.js");
 
 let mockWidgetWindow;
 
@@ -104,10 +100,6 @@ window.widgetWindows = {
     windowFor: jest.fn(() => mockWidgetWindow)
 };
 
-// Wrap source: execute the class definition and assign to global
-const wrappedSource = oscilloscopeSource + "\nglobal.Oscilloscope = Oscilloscope;\n";
-new Function(wrappedSource)();
-
 beforeEach(() => {
     mockWidgetWindow = createMockWidgetWindow();
 

js/widgets/oscilloscope.js

@@ -327,3 +327,7 @@ class Oscilloscope {
         }
     }
 }
+
+if (typeof module !== "undefined") {
+    module.exports = Oscilloscope;
+}