How to find out if certain javascript code is actually used?

javascript jquery legacy-code code-cleanup
Ashkan Aryan picture Ashkan Aryan · May 31, 2013 · Viewed 13.6k times · Source

I am doing some JavaScript cleanup work on a legacy project, and trying to get rid of redundant JS libraries. I have done all the obvious ones (those that are not references from anywhere at all). But there are a number of JS files that are included in all pages (via tiles).

How can I find out whether they are actually used, short of going through content of each and search for each function in them? Is there a smarter/easier way to do this? It's a java based / Spring project if that helps by the way.

Answer

li x picture li x · Jan 16, 2018

One of the latest updates from the chrome dev tools now includes a JS and CSS coverage tab that allows you to see your unused code.

https://developers.google.com/web/updates/2017/04/devtools-release-notes

1) Open the Command Menu.
2) Start typing Coverage and select Show Coverage.

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