Identifying dead Javascript & CSS

I've started to look at identifying dead Javascript and CSS from a largish e-commerce site. It's a site that has been very well built, but has had numerous hands working on it over the years - this means a chance of redundancy Javascript and CSS - thus Technical Debt.


There are a few reasons why I want to do this:

The site currently has two versions - one for desktop, one for mobile. Behind the scenes there are two sets of files (for part of it) - this includes Javascript and CSS. Hopefully we should be able to reduce the code base by looking at consolidation. Would also make moving to responsive design easier in the future if we have a single source for multiple devices.

Is this difficult?


I'd love someone to point me at nice easy way to identify Javascript or CSS no longer in use - but for the life of me I can't see an easy way of doing this.

If only there was an automated tool ... anyone??? please ???

The process

Ok, while I'm waiting for someone to answer my plea, I'll talk you through my process as it stands.

For each Javascript file (of which there are many):

Ultimately I hope to get to a spreadsheets which tells me on which page Javscript is used. Hopefully I should have the odd bit of Javascript which has no dependencies - thus is dead code and can be removed.

As I say the code is actually very well written and has historically been maintained well - so I probably haven't got a lot of dead code to find. This is likely to make it more difficult - the needle in the haystack principal.

As yet, I've spent no time thinking about the CSS - but I'd expect to go down a similar road.## Next steps Work through the process (at least for the Javscript) and see what I get.

About the author:

Mark Taylor is an experience IT Consultant passionate about helping his clients get better ROI from their Software Development.

He has over 20 years Software Development experience - over 15 of those leading teams. He has experience in a wide variety of technologies and holds certification in Microsoft Development and Scrum.

He operates through Red Folder Consultancy Ltd.