diff --git a/src/modules/Elsa.Expressions.JavaScript/Handlers/ConfigureEngineWithVariableTypes.cs b/src/modules/Elsa.Expressions.JavaScript/Handlers/ConfigureEngineWithVariableTypes.cs
index 4b52a254d..29abe6f5a 100644
--- a/src/modules/Elsa.Expressions.JavaScript/Handlers/ConfigureEngineWithVariableTypes.cs
+++ b/src/modules/Elsa.Expressions.JavaScript/Handlers/ConfigureEngineWithVariableTypes.cs
@@ -11,12 +11,19 @@ namespace Elsa.Expressions.JavaScript.Handlers;
 public class ConfigureEngineWithWorkflowVariableTypes(IOptions<ManagementOptions> options) 
     : INotificationHandler<EvaluatingJavaScript>
 {
+    private static readonly Type[] BlacklistedTypes =
+    [
+        typeof(string),
+        typeof(object),
+        // Add more types if needed.
+    ];
+
     /// <inheritdoc />
     public Task HandleAsync(EvaluatingJavaScript notification, CancellationToken cancellationToken)
     {
         var engine = notification.Engine;
         var variableTypes = options.Value.VariableDescriptors
-            .Where(x => x.Type is { ContainsGenericParameters: false} && x.Type != typeof(object))
+            .Where(x => x.Type is { ContainsGenericParameters: false } && !BlacklistedTypes.Contains(x.Type) && !x.Type.IsPrimitive)
             .Select(x => x.Type)
             .ToArray();
         
diff --git a/test/integration/Elsa.JavaScript.IntegrationTests/JavaScriptAndNetTypeTest.cs b/test/integration/Elsa.JavaScript.IntegrationTests/JavaScriptAndNetTypeTest.cs
new file mode 100644
index 000000000..3858ead2a
--- /dev/null
+++ b/test/integration/Elsa.JavaScript.IntegrationTests/JavaScriptAndNetTypeTest.cs
@@ -0,0 +1,71 @@
+using System.Dynamic;
+using System.Numerics;
+using System.Text.Json;
+using Elsa.Common.Converters;
+using Elsa.Expressions.Models;
+using Elsa.JavaScript.Contracts;
+using Elsa.Testing.Shared;
+using Microsoft.Extensions.DependencyInjection;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Elsa.JavaScript.IntegrationTests;
+
+/// <summary>
+/// These tests ensure that we did not replace any JS types with .NET types. 
+/// </summary>
+public class JavaScriptAndNetTypeTest
+{
+    private readonly IServiceProvider _serviceProvider;
+    private readonly IJavaScriptEvaluator _evaluator;
+
+    public JavaScriptAndNetTypeTest(ITestOutputHelper testOutputHelper)
+    {
+        _serviceProvider = new TestApplicationBuilder(testOutputHelper).Build();
+        _evaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
+    }
+
+    [Fact(DisplayName = "Can evaluate JavaScript that returns a string")]
+    public async Task ReturnsJsStringAsDotNetString()
+    {
+        var script = "return String('true')";
+        var result = await EvaluateAsync<string>(script);
+        
+        Assert.Equal("true", result);
+    }
+    
+    [Fact(DisplayName = "Can evaluate JavaScript that returns a string parsed into a Boolean")]
+    public async Task ReturnsJsStringParsedAsDotNetBoolean()
+    {
+        var script = "return String('true')";
+        var result = await EvaluateAsync<bool>(script);
+        
+        Assert.True(result);
+    }
+    
+    [Fact(DisplayName = "Can evaluate JavaScript that constructs a JS Object")]
+    public async Task ReturnsJsObjectAsExpandoObject()
+    {
+        var script = "return Object({})";
+        var result = await EvaluateAsync<object>(script);
+        
+        Assert.NotNull(result);
+        Assert.IsType<ExpandoObject>(result);
+    }
+
+    [Fact(DisplayName = "Can evaluate JavaScript that returns a JS Array")]
+    public async Task ReturnsJsArrayAsDotNetArray()
+    {
+        var script = "return Array(1,2,3)";
+        var result = await EvaluateAsync<int[]>(script);
+
+        Assert.NotNull(result);
+    }
+
+    private async Task<T?> EvaluateAsync<T>(string script)
+    {
+        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new());
+        var type = typeof(T);
+        return (T?)await _evaluator.EvaluateAsync(script, type, expressionExecutionContext);
+    }
+}