SortableList. Harness for applying SortableJS to resources generically.

index.haml

-# app/views/thingies/index.haml
%table
  %thead
    %tr
      %th
      %th Thingy Name
  %tbody#thingyList{data: {sortable_list_url: reorder_thingies_path} }
    - @thingies.order(:position).each do |thingy|
      %tr{data: {sortable_item_id: thingy.id, sortable_item: true}}
        %td
          %i.fas.fa-arrows-v
         %td= thingy.name

:javascript
  new App.SortableList(document.querySelector("#thingyList"))
        
      

sortable-list.coffee

# app/assets/javascripts/sortable-list.coffee
class App.SortableList
  # make the provided element sortable
  # the container element should have a `data-sortable-list-url` that receives the ordering
  # and sortable items should have `data-sortable-id` attributes with their id


  constructor: (@element) ->
    @url = @element.getAttribute('data-sortable-list-url')
    @_initSortable()

  _initSortable: ->
    Sortable.create @element,
      animation: 150
      onEnd: (event) =>
        item_ids = $(@element)
            .children("[data-sortable-item]")
            .toArray()
            .map (item) => item.getAttribute("data-sortable-item-id")

        $.ajax
          url: @url
          data: {sortable_ids: item_ids}
          method: 'POST'
          dataType: 'text/html'

sortable_resource_controller.rb

# app/controllers/concerns/sortable_resource_controller.rb
module SortableResourceController
  extend ActiveSupport::Concern

  def reorder
    params[:sortable_ids].each_with_index do |id, i|
      sortable_resource_repo.where(id: id).update_all position: i+1
    end
    head :ok
  end

  private def sortable_resource_repo
    raise "Abstract Method"
  end

end

thingies_controller.rb

# app/controllers/thingies_controller.rb
class ThingiesController < ApplicationController
  include SortableResourceController
  
  private def sortable_resource_repo
    Thingy.all
  end
end