HashKeyTransformer

Ruby applications typically use underscore (also called "snake_case") as their convention for Hash keys. When sending data from a Ruby application to another application it is often useful to transform the style of hash keys to the style expected by the other application (camelCase or dashed-case for example). Likewise, when receiving data from an external application, it is often useful to transform the style of incoming hash keys to the underscore style common in Ruby.

hash_key_transformer makes it easy to deeply transform a JSON-like data structure from one style of key to another.

The following transformations are supported:

From	To
camel	underscore
underscore	camel
dash	underscore
underscore	dash

Currently, all transformations output Hash keys as :symbols. This could be adjusted if there is interest.

For example, when receiving data from a JavaScript client application, hash_key_transformer can easily transform the following data structure from this:

{
  'keyName1' => 1,
  'keyName2' => [
    {
      'keyName3' => [
        {
          'keyName4' => 4,
          'keyName5' => 5
        }
      ]
    }
  ]
}

to this:

{
  key_name1: 1,
  key_name2: [
    {
      key_name3: [
        {
          key_name4: => 4,
          key_name5: => 5
        }
      ]
    }
  ]
}

Installation

Add this line to your application's Gemfile:

gem 'hash_key_transformer'

And then execute:

$ bundle

Or install it yourself as:

$ gem install hash_key_transformer

Usage

Use the appropriate transformation from this list:

• #transform_camel_to_underscore
• #transform_underscore_to_camel
• #transform_dash_to_underscore
• #transform_underscore_to_dash

For example:

require 'hash_key_transformer'

transformed_object = HashKeyTransformer.transform_camel_to_underscore(object)

Development

Source code for the gem itself is located under the src/gem directory. Source code for the tests is located under src/test. Separating the test source code into a separate project allows the tests to consume the gem source code as a gem, which more closely mirrors actual use by other developers.

Gem

Navigate to src/gem in your terminal.

After checking out the repo, run bin/setup to install gem dependencies.

You can also run bin/console for an interactive prompt that will allow you to experiment.

Publishing Gem Releases

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.

Tests

Navigate to src/test in your terminal.

Run bin/setup to install test dependencies.

Run bundle exec rake to run the tests.

Contributing

Bug reports and pull requests are welcome on GitHub here.