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Talha Aamir
Talha Aamir

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Conditional Debugging - Faster debugging for complicated cases

Introduction

My main goal with this small post is to just point out that if you're someone who doesn't use conditional breakpoints, when:

  • you're investigating a bug
  • know a case (some id or some value) you want to verify
  • are continually hitting the continue or step next button

NOTE For the TLDR of this post in a short gif, skip to conditional debugging

Well, you should (be using conditional breakpoints). Its a pretty simple feature which most (if not all) debug tools support. I have no idea how I skipped past this, probably because I never realized I could do this in the first place.

Caveat

At the time of writing, I have been using this for python debugging using pycharm, c++ debugging using visual studio and javascript debugging in chrome devtools, and it seems to be atrociously slow in devtools at my work atleast, even for an array with a few 100 entries, not a complicated process at all, but a bug I imagine. Either way, it's worth testing out yourself

Process

Setup

I'll take chrome dev tools as an example here, I have created a very simple project, with an html file that has a button with a function printEvenTillN. This as you might image prints all even numbers till N.
I have another js file, what this has is the function itself.
I have used the Live Server extension to launch a server so I can debug this in chrome devtools.

Conditional Debugging

The Case I am presenting is that for our simple function printEvenTillN I want to see if 32 is amongst the numbers it prints. I am choosing a specific number because it translates well to complicated debugging cases where we want to see if say a particular element with some known unique id exists.

Conditional Debugging Demo

Conclusion

I hope you get some value out of it. If you did not know about this already I encourage you to try it. Whilst console logs and looping through each debug instance is well, easy, and we are sometimes lazy, this makes the process so much easier.

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