MeFirst

A straighforward extension for ActiveRecord models which makes it easy to reorder objects by a given column's values.

lemon-line

Getting Started

Add this line to your application's Gemfile:

gem 'me_first'

And then execute:

$ bundle

Or install it yourself as:

$ gem install me_first

Usage

Installation

To use MeFirst, you need to:

  1. Add an integer ordering column to your model.
  2. Require MeFirst in your model.
  3. Use MeFirst's attr_orderable method with the ordering column as an argument.

So:

$ rails g migration add_column_order_to_fake_models order:integer
$ rake db:migrate

class FakeModel
    include MeFirst
    attr_orderable :order
end

That's it! You're now ready to reorder by order (or whichever column name you want) at will.

Commands

MeFirst gives you a number of commands, named based on the given column. For the above example, you're given two scopes:

FakeModel.by_order
FakeModel.by_reverse_order

And a number of useful instance methods:

instance = FakeModel.first
instance.move_order_up!(2) # Moves the instance's order up by 2 places
instance.move_order_down!(1) # Moves the instance's order down by 1 place
instance.move_order_to_end!
instance.move_order_to_beginning!
instance.set_order!(5) # Sets the current instance's order to 5, and reorders other instances around it.

To get a clearer sense of what exactly these methods do, check out the specs.

Note that these methods are all dependent upon the column name:

class FakeModel
    include MeFirst
    attr_orderable :position
end

FakeModel.by_position
FakeModel.first.move_position_up!(5)

Performance Note

This works great for relatively small numbers of objects. When dealing with a large table of ordered objects, MeFirst (and ordering by column in general), will not be particularly performant -- resetting a single instance's order requires changing the order of all the objects which followed its initial location.

Development

After checking out the repo, run bin/setup to install dependencies. Then, 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 to create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

  1. Fork it ( https://github.com/sashafklein/me_first/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request