ObjectExplorer is a simple gem that separates the concern of traversing nested hash/array data structures (like those you would find among ActiveRecord associations). Unlike Rails 6.x's #deep_transform_values, it can handle any mix of nested hashes and arrays. Standard usage is below. There is also a utility method to generate diffs between objects.

Add this line to your application's Gemfile:

gem 'object_explorer'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install object_explorer

Typical usage is to initialize a new ObjectExplorer, passing in an object of interest. Then call explore to examine it and return some report on found nodes. The default selection mechanism returns all nodes, and the default report returns the node itself, so without parameters, the #explore method will just return the original object.

my_explorer = ObjectExplorer.new(object_with_nested_hashes_and_arrays)
my_selection_proc = ->(node, _path, _tree) { <some criteria that resolve to a boolean> }
my_reporting_proc = ->(node, _path, _tree) { <any output appropriate to your needs> }
report = my_explorer.explore(select: my_selection_proc, report: my_reporting_proc)

The output is in a structure which mimics the initial object, but with only nodes representing those values selected from within the original object.

In the case of arrays, unselected objects will not be reported, so the reported array in the output will only have elements representing selected nodes. If you wish to preserve the indices of elements in arrays, pass preserve_array_indexes: true to #explore.

There is also a #diff utility, which receives an object for comparison, but otherwise has the same signature as #explore

diff_report = my_explorer.diff(some_other_object, <optional_reporting_proc>)

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/bgarr/object_explorer. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the ObjectExplorer project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.