Unused
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A command line tool to identify unused code.

Unused usage

Languages

Unused is best leveraged with dynamic programming languages including Elixir and Ruby. That said, it can be used with any project, as long as it has a tags file.

Pull Requests

Want to see Unused in action? Here are 3 pull requests demonstrating its use.

Installation

You can install my formulae via Homebrew with brew tap:

$ brew tap joshuaclayton/formulae

Next, run:

$ brew install unused

To update to the latest available version of Unused:

$ brew update
$ brew upgrade unused

If you're not using Homebrew, you can read about alternative installation options.

Why?

Unused code is expensive. People have a limited amount of room in their working memory; by filling working memory with unused code when dissecting a problem, developers are immediately at a disadvantage as there's less room to reason about parts of the codebase that are actually in use.

I like cooking, so here's an analogy.

Imagine you're cooking dinner, and you're washing dishes as you go. An empty sink when you're washing dishes means your hands are free to organize things, to work more quickly, to speed through simple tasks and continue onward.

Unused code would be working with a sink stacked high with flatware, dishes, knives. It will actively slow you down, but once those items are removed, you're able to operate more freely again.

How?

Unused leverages work done by Exuberant Ctags by collecting the list of tokens and searching the codebase with the Silver Searcher for each occurrence. With those results, it classifies occurrences into different buckets, determining if it's part of the test suite.

Once searching is complete, it analyzes usage patterns based on general guidelines and calculates a likelihood for whether it's able to be removed; in Rails for example, controller names (UsersController) are likely never referred to by that exact name; instead, the Rails router uses a symbol to refer to it instead (e.g. resources :users, only: [:index, :show]).

Support

Please contact me on Twitter or include @joshuaclayton on your pull requests (either GitHub or BitBucket) if you're using Unused.