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- Add `checked_value` and `unchecked_value` arguments
- Update links in docs to official Rails docs

doc/development/fe_guide/haml.md

@@ -53,5 +53,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 | `method` | Attribute on the object passed to `gitlab_ui_form_for`. | `Symbol` | `true` |
 | `label` | Checkbox label. | `String` | `true` |
 | `help_text` | Help text displayed below the checkbox. | `String` | `false` (`nil`) |
-| `checkbox_options` | Options that are passed to [Rails `check_box` method](https://apidock.com/rails/ActionView/Helpers/FormHelper/check_box). | `Hash` | `false` (`{}`) |
-| `label_options` | Options that are passed to [Rails `label` method](https://apidock.com/rails/ActionView/Helpers/FormHelper/label). | `Hash` | `false` (`{}`) |
+| `checkbox_options` | Options that are passed to [Rails `check_box` method](https://api.rubyonrails.org/classes/ActionView/Helpers/FormBuilder.html#method-i-check_box). | `Hash` | `false` (`{}`) |
+| `checked_value` | Value when checkbox is checked. | `String` | `false` (`'1'`) |
+| `unchecked_value` | Value when checkbox is unchecked. | `String` | `false` (`'0'`) |
+| `label_options` | Options that are passed to [Rails `label` method](https://api.rubyonrails.org/classes/ActionView/Helpers/FormBuilder.html#method-i-label). | `Hash` | `false` (`{}`) |

lib/gitlab/form_builders/gitlab_ui_form_builder.rb

@@ -3,13 +3,25 @@
 module Gitlab
   module FormBuilders
     class GitlabUiFormBuilder < ActionView::Helpers::FormBuilder
-      def gitlab_ui_checkbox_component(method, label, help_text: nil, checkbox_options: {}, label_options: {})
+      def gitlab_ui_checkbox_component(
+        method,
+        label,
+        help_text: nil,
+        checkbox_options: {},
+        checked_value: '1',
+        unchecked_value: '0',
+        label_options: {}
+      )
         @template.content_tag(
           :div,
           class: 'gl-form-checkbox custom-control custom-checkbox'
         ) do
           @template.check_box(
-            @object_name, method, format_options(checkbox_options, ['custom-control-input'])
+            @object_name,
+            method,
+            format_options(checkbox_options, ['custom-control-input']),
+            checked_value,
+            unchecked_value
           ) +
           @template.label(
             @object_name, method, format_options(label_options, ['custom-control-label'])

spec/lib/gitlab/form_builders/gitlab_ui_form_builder_spec.rb

@@ -41,15 +41,17 @@ RSpec.describe Gitlab::FormBuilders::GitlabUiFormBuilder do
         {
           help_text: 'Instead of all the files changed, show only one file at a time.',
           checkbox_options: { class: 'checkbox-foo-bar' },
-          label_options: { class: 'label-foo-bar' }
+          label_options: { class: 'label-foo-bar' },
+          checked_value: '3',
+          unchecked_value: '1'
         }
       end
 
       it 'renders help text' do
         expected_html = <<~EOS
           <div class="gl-form-checkbox custom-control custom-checkbox">
-            <input name="user[view_diffs_file_by_file]" type="hidden" value="0" />
-            <input class="custom-control-input checkbox-foo-bar" type="checkbox" value="1" name="user[view_diffs_file_by_file]" id="user_view_diffs_file_by_file" />
+            <input name="user[view_diffs_file_by_file]" type="hidden" value="1" />
+            <input class="custom-control-input checkbox-foo-bar" type="checkbox" value="3" name="user[view_diffs_file_by_file]" id="user_view_diffs_file_by_file" />
             <label class="custom-control-label label-foo-bar" for="user_view_diffs_file_by_file">
               <span>Show one file at a time on merge request&#39;s Changes tab</span>
               <p class="help-text">Instead of all the files changed, show only one file at a time.</p>
@@ -59,6 +61,22 @@ RSpec.describe Gitlab::FormBuilders::GitlabUiFormBuilder do
 
         expect(checkbox_html).to eq(html_strip_whitespace(expected_html))
       end
+
+      it 'passes arguments to `check_box` method' do
+        allow(fake_template).to receive(:check_box).and_return('')
+
+        checkbox_html
+
+        expect(fake_template).to have_received(:check_box).with(:user, :view_diffs_file_by_file, { class: %w(custom-control-input checkbox-foo-bar), object: user }, '3', '1')
+      end
+
+      it 'passes arguments to `label` method' do
+        allow(fake_template).to receive(:label).and_return('')
+
+        checkbox_html
+
+        expect(fake_template).to have_received(:label).with(:user, :view_diffs_file_by_file, { class: %w(custom-control-label label-foo-bar), object: user })
+      end
     end
   end