Change multi_list to allow preserving choice order

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Change log
 
+## [v0.23.2] - 2023-01-11
+
+### Changed
+* Change multi_select to allow preserve user choice ordering
+
 ## [v0.23.1] - 2021-04-17
 
 ### Changed

README.md

@@ -99,6 +99,7 @@ Or install it yourself as:
       * [2.6.3.7 :filter](#2637-filter)
       * [2.6.3.8 :min](#2638-min)
       * [2.6.3.9 :max](#2639-max)
+      * [2.6.3.10 :preserve_order](#26310-preserve_order)
     * [2.6.4 enum_select](#264-enum_select)
       * [2.6.4.1 :per_page](#2641-per_page)
       * [2.6.4.1 :disabled](#2641-disabled)
@@ -1153,6 +1154,22 @@ prompt.multi_select("Select drinks?", choices, max: 3)
 # ‣ ⬡ bourbon
 ```
 
+#### 2.6.3.10 `:preserve_order`
+
+To preserve the ordering of an user selections, use the `:preserve_order` option:
+
+```ruby
+choices = %w(vodka beer wine whisky bourbon)
+prompt.multi_select("Select drinks?", choices, preserve_order: true)
+# =>
+# Select drinks? (max. 3) beer, vodka, whisky
+#   ⬢ vodka
+#   ⬢ beer
+#   ⬡ wine
+#   ⬢ whisky
+# ‣ ⬡ bourbon
+```
+
 ### 2.6.4 enum_select
 
 In order to ask for standard selection from indexed list you can use `enum_select` and pass question together with possible choices:

lib/tty/prompt/multi_list.rb

@@ -2,6 +2,7 @@
 
 require_relative "list"
 require_relative "selected_choices"
+require_relative "ordered_selected_choices"
 
 module TTY
   class Prompt
@@ -18,7 +19,8 @@ class MultiList < List
       # @api public
       def initialize(prompt, **options)
         super
-        @selected = SelectedChoices.new
+        @preserve_order = options.fetch(:preserve_order, false)
+        @selected = selected_choices_klass.new
         @help = options[:help]
         @echo = options.fetch(:echo, true)
         @min  = options[:min]
@@ -71,7 +73,7 @@ def keyspace(*)
       def keyctrl_a(*)
         return if @max && @max < choices.size
 
-        @selected = SelectedChoices.new(choices.enabled, choices.enabled_indexes)
+        @selected = selected_choices_klass.new(choices.enabled, choices.enabled_indexes)
       end
 
       # Revert currently selected choices when Ctrl+I is pressed
@@ -84,7 +86,7 @@ def keyctrl_r(*)
                     acc << idx if !choice.disabled? && !@selected.include?(choice)
                     acc
                   end
-        @selected = SelectedChoices.new(choices.enabled - @selected.to_a, indexes)
+        @selected = selected_choices_klass.new(choices.enabled - @selected.to_a, indexes)
       end
 
       private
@@ -102,7 +104,7 @@ def setup_defaults
             choices.index(choices.find_by(:name, d.to_s))
           end
         end
-        @selected = SelectedChoices.new(@choices.values_at(*default_indexes),
+        @selected = selected_choices_klass.new(@choices.values_at(*default_indexes),
                                         default_indexes)
 
         if @default.empty?
@@ -219,6 +221,16 @@ def render_menu
 
         output.join
       end
+
+      # Render either SelectedChoices or OrderedSelectedChoices based on preserve_order option
+      #
+      # @return [Class]
+      #
+      # @api private
+      def selected_choices_klass
+        return OrderedSelectedChoices if @preserve_order
+        SelectedChoices
+      end
     end # MultiList
   end # Prompt
 end # TTY

lib/tty/prompt/ordered_selected_choices.rb

@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+module TTY
+  class Prompt
+    # @api private
+    class OrderedSelectedChoices
+      include Enumerable
+
+      attr_reader :size
+
+      # Create ordered selected choices
+      #
+      # @param [Array<Choice>] selected
+      # @param [Array<Integer>] indexes (ignored)
+      #
+      # @api public
+      def initialize(selected = [], _indexes = [])
+        @selected = selected
+        @size = @selected.size
+      end
+
+      # Clear ordered selected choices
+      #
+      # @api public
+      def clear
+        @selected.clear
+        @size = 0
+      end
+
+      # Iterate over ordered selected choices
+      #
+      # @api public
+      def each(&block)
+        return to_enum unless block_given?
+
+        @selected.each(&block)
+      end
+
+      # Insert choice at the end
+      #
+      # @param [Integer] index (ignored)
+      # @param [Choice] choice
+      #
+      # @api public
+      def insert(_index, choice)
+        @selected << choice
+        @size += 1
+        self
+      end
+
+      # Delete choice at index
+      #
+      # @return [Choice]
+      #   the deleted choice
+      #
+      # @api public
+      def delete_at(index)
+        return nil if index < 0
+        return nil if index >= @size
+
+        choice = @selected.delete_at(index)
+        @size -= 1
+        choice
+      end
+
+      def find_index_by(&search)
+        (0...@size).bsearch(&search)
+      end
+    end # OrderedSelectedChoices
+  end # Prompt
+end # TTY

lib/tty/prompt/version.rb

@@ -2,6 +2,6 @@
 
 module TTY
   class Prompt
-    VERSION = "0.23.1"
+    VERSION = "0.23.2"
   end # Prompt
 end # TTY

spec/unit/multi_select_spec.rb

@@ -905,4 +905,34 @@ def exit_message(prompt, choices)
       expect(prompt.output.string).to eq(expected_output)
     end
   end
+
+  context "with :preserve_order" do
+    it "preserves user choice ordering" do
+      choices = %w[A B C]
+      prompt.on(:keypress) { |e|
+        prompt.trigger(:keyup)   if e.value == "k"
+        prompt.trigger(:keydown) if e.value == "j"
+      }
+      prompt.input << " " << "j" << " " << "j" << " " << "k" << " " << " " << "\r"
+      prompt.input.rewind
+
+      value = prompt.multi_select("What letter?", choices, preserve_order: true, per_page: 100)
+      expect(value).to eq(%w[A C B])
+
+      expected_output =
+        output_helper("What letter?", choices, "A", [], init: true, preserve_order: true,
+          hint: "Press #{up_down} arrow to move, Space/Ctrl+A|R to select (all|rev) and Enter to finish") +
+        output_helper("What letter?", choices, "A", %w[A], preserve_order: true) +
+        output_helper("What letter?", choices, "B", %w[A], preserve_order: true) +
+        output_helper("What letter?", choices, "B", %w[A B], preserve_order: true) +
+        output_helper("What letter?", choices, "C", %w[A B], preserve_order: true) +
+        output_helper("What letter?", choices, "C", %w[A B C], preserve_order: true) +
+        output_helper("What letter?", choices, "B", %w[A B C], preserve_order: true) +
+        output_helper("What letter?", choices, "B", %w[A C], preserve_order: true) +
+        output_helper("What letter?", choices, "B", %w[A C B], preserve_order: true) +
+        exit_message("What letter?", %w[A C B])
+
+      expect(prompt.output.string).to eq(expected_output)
+    end
+  end
 end

spec/unit/ordered_selected_choices_spec.rb

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+RSpec.describe TTY::Prompt::OrderedSelectedChoices do
+  it "inserts choices at the end" do
+    choices = %w[A B C D E F]
+    selected = described_class.new
+
+    expect(selected.to_a).to eq([])
+    expect(selected.size).to eq(0)
+
+    selected.insert(5, "F")
+    selected.insert(1, "B")
+    selected.insert(3, "D")
+    selected.insert(0, "A")
+    selected.insert(4, "E")
+    selected.insert(2, "C")
+
+    expect(selected.to_a).to eq(["F", "B", "D", "A", "E", "C"])
+    expect(selected.size).to eq(6)
+
+    expect(selected.delete_at(3)).to eq("A")
+  end
+
+  it "initializes with selected choices" do
+    choices = %w[A B C D E F]
+    selected = described_class.new(choices, (0...choices.size).to_a)
+
+    expect(selected.to_a).to eq(choices)
+    expect(selected.size).to eq(6)
+
+    choice = selected.delete_at(3)
+    expect(choice).to eq("D")
+
+    expect(selected.to_a).to eq(%w[A B C E F])
+    expect(selected.size).to eq(5)
+  end
+
+  it "inserts and deletes choices" do
+    selected = described_class.new
+
+    selected.insert(5, "F")
+    selected.insert(1, "B")
+    selected.insert(3, "D")
+    selected.insert(0, "A")
+
+    expect(selected.to_a).to eq(%w[F B D A])
+    expect(selected.size).to eq(4)
+
+    choice = selected.delete_at(2)
+    expect(choice).to eq("D")
+    expect(selected.to_a).to eq(%w[F B A])
+    expect(selected.size).to eq(3)
+
+    selected.insert(4, "E")
+    choice = selected.delete_at(-999)
+
+    expect(choice).to eq(nil)
+    expect(selected.to_a).to eq(%w[F B A E])
+    expect(selected.size).to eq(4)
+  end
+
+  it "clears choices" do
+    selected = described_class.new(%w[B D F])
+
+    expect(selected.to_a).to eq(%w[B D F])
+    expect(selected.size).to eq(3)
+
+    selected.clear
+
+    expect(selected.to_a).to eq([])
+    expect(selected.size).to eq(0)
+  end
+end