MiniTree

MiniTree is a Rails gem to display and handle a treeview. It supports moving/reordering items in the treeview, collapsing/expanding of a subtree and creating/deleting them.

Items in the treeview can be enhanced with links to trigger actions.

MiniTree requires just a basic Rails system. Specifically, besides Stimulus no other Javascript package (i.e jQuery) is expected. Configuration is absent.

MiniTree includes a javascript component to handle the view on the client side as well as code for the server side.

Some preparation for the usage is required:

• an additional database table storing the tree structure
• a legend method in the model
• a call to MiniTree to initialize the tree structure
• calls in the model to miniTree during creation, update and deletion of an item

# ./app/models/<model>.rb
class <model> < ApplicationRecord
  def legend = "#{name} #{id}"   # an example
end

# ./app/models/<model>_tree.rb
class <model>Tree < ApplicationRecord
  include MiniTree::Utils
end

# ./db/migrate/<nnn>_create_<model>_trees.rb
class Create<Model>Trees < ActiveRecord::Migration[8.0]
  def change
    create_table :<model>_trees do |t|
      t.string :legend
      t.integer :parent_id, index: true
      t.integer :position, null: false, default: 0
      t.boolean :collapsed, default: false
      t.string :kind

      t.timestamps
    end
    # add_foreign_key :items, :items, column: :parent_id
  end
end

You may specify your view of an item in the treeview:

# ./app/views/application/_mini_tree_title.html.erb
# id and legend are defined
<%= link_to "action", edit_<model>(id:) %>
<%= legend %>

<Model>Tree.refresh
<Model>Tree.create_item(<id>, <legend>)
<Model>Tree.destroy_item(<id>)
<Model>Tree.update_item(<id>, <legend>)

# Example
<% list = <Model>Tree.all %>
<%= render "mini_trees/index", locals: {list:} %>

As usual:

# Gemfile
...
gem "mini_tree"
...

and run "bundle install".

Furthermore, copy manually app/javascript/controllers/tree_controller.js from the gem mini_tree into your own app/javascript/controllers/ directory.

This software has been developed and tested with:

• Ubuntu 24.04
• Ruby 3.4.7
• Rails 8.1.1

See also:

• ./.github/workflows/rake.yml

No particular system dependency is known, i.e. mini_tree is expected to run on other systems without trouble.

There are quite a lot of TreeViews available. If you are curious you may search in particular for:

• jqTree
• sortableJS

Copyright (c) 2025 Dittmar Krall (www.matiq.com), released as open source under the terms of the MIT license.