Ignoring Minified Javascript Files with Ack 2

The reason I got involved with the ack project about a year ago was because I had an itch to scratch: I wanted ack to ignore files containing minified Javascript. My need for this has since lessened, but I still contribute to the ack project, and I still encounter this from time to time. Fortunately, with the release of the ack 2.0 alpha last week, support for this has been improved.

First of all, ack 2 ignores files ending in .min.js by default, so if you're using that naming scheme, you should already be happy! However, not every project does this. Here's a little ackrc snippet you can stick in your .ackrc at your project root that should help:

--ignore-file=firstlinematch:/.{200}/

All this code does is tell ack to not search any files that have a first line longer than or as long as 200 characters, which is fairly typical of minified Javascript. However, this solution has two potential problems:

• Some minified Javascript files include a "header", usually containing copyright information or something. This fix will not help you there, unless you remove the headers.
• This change makes ack open every file in your project, which can slow things own a bit.

It's only an alpha release, so I hope to make some progress on making a more complete solution for the final release of ack 2.0.

-Rob