Debug for javascript code

Question

I am working on a MVC application, and would like some code in JavaScript to run only if I am in debug mode. I do not want that code to run when I release the code.

In other words, is there anything similar to the following code in C#, for javascript / jQuery?

#if (DEBUG)
 // debugging code block here
#else
 // release code block here
#endif

• Dave Chen: following code in C# for javascript some code in javascript Which language?! Above snippet looks fine...
• adeneo: Just create a global called DEBUG, but you should really remove all debugging code on a production site, so I don't see the point ?
• TK1: the way my application is designed, I use a different set of variables when debugging than in production. so I do need this kind of a functionality for my application..

Answer 1

I'd suggest using the construct in your question and setting something in your viewmodel to include/exclude the javascript.

public ActionResult XXX()
{
 var vm=new MyViewModel(); //or just use ViewBag/ViewData
#if (DEBUG)
 vm.RunJS=true;
#else
 vm.RunJS=false;
#endif
 return View(vm);
}

then in your view

@if(Model.RunJS)
{
 <script ...></script>
}

or use a similar construct to pass the DEBUG status through to your javascript.

<script type="text/javascript">
 startMyJavascript(@Model.IsDebug?"true":"false");
</script>

(not so sure about Razor syntax, but I think the above is good)

• Dave Chen: +1, debug code in JavaScript is submitted regardless if it's required/not. If you can stop the code directly from the back-end that would be the best option.
• TK1: I want to run parts of the code in the JS file, depending upon the debug state. I don't want to include / exclude files ...
• spender: @TK1: Javascript running in the browser has no awareness of the DEBUG (or otherwise) status of your backend. You need to pass it through the View as I suggest above.
• DividedByZero: @TK1 this isn't including files.. in ASP.NET when you do this: if(1 == 2)alert("hey") else alert("hi") the javascript received by the browser is: alert("hi")

Answer 2

Sure. Here is the JavaScript version.

var DEBUG = true;
if(DEBUG) {
 // debug code
} else {
 // production code
}

• TK1: oh, I wanted to know if I can use the variable from the visual studio compiler. Basically, I can compile code from visual studio, under Debug mode, or release mode ...
• TK1: I ended up using this kind of a solution for this scenario, so I am going to mark this as answer.

Answer 3

You can always use the ViewBag along with @Html.Raw(). I do this occasionally and it works well.

Controller:

#if DEBUG
 ViewBag.JavaScript = "String representation of JS code";
#endif
 return View();

View:

@Html.Raw(ViewBag.JavaScript)

I would also recommend using an include such as

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>

rather than the raw JavaScript to avoid having to put all of that mess in your controller.