Debugging JavaScript

This is an end-to-end technical post, if there are any readers who are not technically savvy, please excuse me. But this one excites me such a lot that I can’t wait till I post this sooner.

As a software tester, I have limited knowledge about software development. But, being an API and automation tester, I work a lot with programming languages. One thing that helps me (in fact, there are two;-); I will write more on them in a future post) carry on with my programming works is the debugger. Debugger as most of us know is one of the most standard features of almost all programming languages that come with an IDE, including C, C++, all .NET languages, Java etc. Debuggers are available even for some scripting languages including Perl, Python, Ruby etc, as separate products. For the past 2 years, I had been testing the APIs exposed by our product with C# & VB6.0 and one of my colleagues test them with JavaScript. JavaScript is one of those scripting languages like the ones I mentioned above, but has one major drawback. It doesn’t have a proper IDE yet and hence no debugger. So, when my dear friend asked me to take this thing over, due to some other priority assignments for him, I was not very short of terrified. I had to learn something new is a short period of time (my friend consoled me saying that learning JavaScript is simple and that it is very similar to many other scripting languages, which I already knew) and also be productive soon. I started searching for tools that will help me debugging, before I learnt much about the language as such…Till yesterday, I was more or less successful. I found that one of my favorite IDEs used with many scripting environments (including Perl) – Komodo – recently released the alpha version of their product that will help JavaScript debugging in Firefox browser. I wasted no time in trying it out, but couldn’t get it to work properly. But, being in Alpha, Komodo 4.0 still holds promises in its final release.

When I searched around in Google, I found that there are couple of other options, but some of them are priced and yet others seemed to be too fragile. I didn’t obviously want to try out the priced options, because unless sure of it, I didn’t want to spend any money on them.

But, then today evening, I discovered something fantastic with the help of one of my colleagues from our development team. And, the most interesting aspect of it is that I had been using it for the past 2 years for other purposes, but unaware of all its use. As a C# programmer for the past 2 years, Visual Studio NET IDE is very familiar to me. What I discovered yesterday was, you could use the .NET IDE as a debugger for JavaScript. But, the use is not straight-forward as in the case with the .NET languages. JavaScript runs typically in a browser client, but debugging is not directly possible in the browser. There are no browsers available yet, with debugging capabilities. But, .NET IDE provides a way to attach the process in which the browser is running. As soon as the process is attached, it opens a read-only version of the JavaScript code and it internally creates maps for the debug symbols and the source code line-by-line. It works with native JavaScript objects, as well as external objects including COM. Try it out. It works great!

PS: avi attached...