Fun with Ripgrep, part 1

2 minutes
cartoon of doom guy from doom 2016, saying "rip and tear!!!"

Design systems have a tendency to get out of hand if you don't pay close attention. Ever wanted to know how many similarly-named elements you have in your repo? We need to find all tag name instances which start with rh-navigation-, and end with at least two dash-separated words. Why two? Because we already know that we want to have <rh-navigation-primary>, <rh-navigation-secondary>, etc - that's the whole feature, but we don't necessarily want to have similar-sounding, nearly-identical child elements like <rh-navigation-primary-item> and <rh-navigation-secondary-item>. As the wisest of men once said

There is a time and a season for everything under the sun A time to copy, A time to abstract A time to test, A time to do static analysis

etc.

Ripgrep to the rescue! Here's the one-liner I used:

rg -Ior '$1' "<(rh-navigation(-\w+){2,})( .*)?>" | sort | uniq

Breakdown:

  • rg - the ripgrep command. Rips and tears, until it's done
  • -I - the --no-filename flag prevents ripgrep from printing file names, this is important because we don't care which filename is there, only which tag name is there
  • -o - the --only-matching flag only prints the matching parts of the line, this is important for the same reason as above
  • -r '$1' - the --replace flag replaces the match ripgrep finds with the regexp expression provided, namely the (shell-escaped with ') first capture group, which is from...
  • <(rh-navigation-(\w+){2,})( .*)?> - the pattern we're searching for. In my case, I'm looking for auxiliary elements that have to do with (but aren't equivalent) to our <rh-navigation-*> suite of elements.
    • the first capture group is rh-navigation-(\w+){2,}, which means that the tag name
      1. must begin with rh-navigation-
      2. must then be followed by a dash, followed by one or more alpha numeric character (\w for word chars, + meaning one-or-more)
      3. that "-word" pattern must repeat two-or-more times. e.g. rh-navigation-primary-item will match, but rh-navigation-primary won't
    • ( .*)? optional attributes on the element, preceeding the closing >
  • | sort - we pipe those results (tag names, no attributes, at least 4 words each) into the sort command, which is a necessary step before ...
  • | uniq - we pipe the sorted results into the uniq command which returns (by default) a list of unique entries

And thus, we've discovered all the tag names in our repo which are auxiliary elements to the rh-navigation suite of elements.

Cover image CC BY-NC-SA theeysmaster