Prioritize

Allows you to sort both simple and nested lists (for example, lists based on the closure_tree gem).

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Important! Works only with PostgreSQL and SQLite databases. In PostgreSQL, data is updated in 1 query, in SQLite, the "ActiveRecord" algorithm is used (select data -> iterate-transform -> save)

Prioritize adds the following features:

1. Adds a method .priority_after(prev_id, moved_id) to the class and class instance, which will update the values of the my_column column (specified in the settings) so that when Section.order(my_column: :asc) the moved element followed the prev.

2. If, when saving a model instance, in the additional field priority_prev specify the identifier of the previous element or the string '^' (when moving to the beginning), then the behavior will work and the values of the my_column column will be updated in accordance with the movement.

Add this line to your application's Gemfile:

gem 'prioritize', '~> 1.1'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install prioritize

Perform a similar migration for your model if necessary:

add_column :sections, "order", :integer , null: false, default: 0
add_index :sections, "order"

Add a setup method to the class code:

class Section < ApplicationRecord
  prioritize_column(:order)
end

The setup is over, we observe the result in the console:

# Let's create multiple instances
Section.create
=> #<Section... id: 1, order: 0...>
Section.create
=> #<Section... id: 2, order: 0...>

# Let's derive the identifiers with the required order.
Section.order(order: :asc).pluck(:id)
=> [1, 2]

# Priority: 2 followed by 1
Section.priority_after(2, 1)
Section.order(order: :asc).pluck(:id)
=> [2, 1]

# Move element 1 to the beginning
Section.find(1).priority_after(nil)
Section.order(order: :asc).pluck(:id)
=> [1, 2]

When moving elements on the frontend (for example, with jquery-ui), we need to send a PATCH request to the controller of the following nature with an additional priority_prev field:

$.ajax({
  url: "/sections/1.json",
  type: "PATCH",
  data: {
    section: {
      priority_prev: 2
    }
  }
})

In the controller, the priority_prev parameter must be enabled:

  def section_params
    params.require(:section).permit(
      ...
      :order,
      :priority_prev
    )
  end

If there is a value in the priority_prev field, a callback will be fired in which the .priority_after method is called.

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] (https://rubygems.org).

bundle
rake spec

Bug reports and pull requests are welcome on GitHub at https://github.com/Zlatov/prioritize.

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