Add component wrapper helper to error alert component

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ## Unreleased
 
+* Add component wrapper to error alert component ([PR #4287](https://github.com/alphagov/govuk_publishing_components/pull/4287))
 * Add new chart component options ([PR #4318](https://github.com/alphagov/govuk_publishing_components/pull/4318))
 * Add shared helper and component wrapper helper to govspeak component ([PR #4325](https://github.com/alphagov/govuk_publishing_components/pull/4325))
 

app/models/govuk_publishing_components/component_wrapper_helper_options.rb

@@ -12,6 +12,7 @@ def self.description
 - `lang` - accepts a language attribute value
 - `open` - accepts an open attribute value (true or false)
 - `hidden` - accepts an empty string, 'hidden', or 'until-found'
+- `tabindex` - accepts an integer. The integer can also be passed as a string.
       "
     end
   end

app/views/govuk_publishing_components/components/_error_alert.html.erb

@@ -4,9 +4,16 @@
   id ||= nil
   description ||= nil
   data_attributes ||= {}
+
+  component_helper = GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(local_assigns)
+  component_helper.set_id(id)
+  component_helper.add_class("gem-c-error-alert govuk-!-display-none-print")
+  component_helper.add_data_attribute({ module: "initial-focus" })
+  component_helper.add_role("alert")
+  component_helper.set_tabindex("-1")
 %>
 
-<%= tag.div id: id, class: "gem-c-error-alert govuk-!-display-none-print", data: { module: "initial-focus" }.merge(data_attributes), role: "alert", tabindex: "-1" do %>
+<%= tag.div(**component_helper.all_attributes) do %>
   <% if description.present? %>
     <%= tag.h2 message, class: "gem-c-error-summary__title" %>
     <%= tag.div description, class: "gem-c-error-summary__body" %>

app/views/govuk_publishing_components/components/docs/error_alert.yml

@@ -1,5 +1,6 @@
 name: Error alert
 description: Used at the top of the page, to summarise a unsuccessful user action.
+uses_component_wrapper_helper: true
 accessibility_criteria: |
   - should be focused on page load, to ensure the message is noticed by
     assistive tech

lib/govuk_publishing_components/presenters/component_wrapper_helper.rb

@@ -12,6 +12,7 @@ def initialize(options)
         check_lang_is_valid(@options[:lang]) if @options.include?(:lang)
         check_open_is_valid(@options[:open]) if @options.include?(:open)
         check_hidden_is_valid(@options[:hidden]) if @options.include?(:hidden)
+        check_tabindex_is_valid(@options[:tabindex]) if @options.include?(:tabindex)
       end
 
       def all_attributes
@@ -25,6 +26,7 @@ def all_attributes
         attributes[:lang] = @options[:lang] unless @options[:lang].blank?
         attributes[:open] = @options[:open] unless @options[:open].blank?
         attributes[:hidden] = @options[:hidden] unless @options[:hidden].nil?
+        attributes[:tabindex] = @options[:tabindex] unless @options[:tabindex].blank?
 
         attributes
       end
@@ -69,6 +71,11 @@ def set_hidden(hidden_attribute)
         @options[:hidden] = hidden_attribute
       end
 
+      def set_tabindex(tabindex_attribute)
+        check_tabindex_is_valid(tabindex_attribute)
+        @options[:tabindex] = tabindex_attribute
+      end
+
     private
 
       def check_id_is_valid(id)
@@ -146,6 +153,16 @@ def check_hidden_is_valid(hidden_attribute)
         end
       end
 
+      def check_tabindex_is_valid(tabindex_attribute)
+        return if tabindex_attribute.blank?
+
+        tabindex_attribute = tabindex_attribute.to_s
+
+        unless /^-?[0-9]+$/.match?(tabindex_attribute)
+          raise(ArgumentError, "tabindex_attribute attribute (#{tabindex_attribute}) is not recognised")
+        end
+      end
+
       def extend_string(option, string)
         ((@options[option] ||= "") << " #{string}").strip!
       end

spec/lib/govuk_publishing_components/components/component_wrapper_helper_spec.rb

@@ -13,6 +13,7 @@
         lang: "en",
         open: true,
         hidden: "",
+        tabindex: "0",
       }
       component_helper = GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(args)
       expected = {
@@ -27,6 +28,7 @@
         lang: "en",
         open: true,
         hidden: "",
+        tabindex: "0",
       }
       expect(component_helper.all_attributes).to eql(expected)
     end
@@ -218,5 +220,65 @@
       helper.set_hidden("hidden")
       expect(helper.all_attributes[:hidden]).to eql("hidden")
     end
+
+    it "can set an tabindex attribute, overriding a passed value" do
+      helper = GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: -1)
+      helper.set_tabindex("1")
+      expect(helper.all_attributes[:tabindex]).to eql("1")
+    end
+
+    describe "tabindex value regex" do
+      it "accepts string numbers" do
+        component_helper = GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: "-984347284732")
+        expected = {
+          tabindex: "-984347284732",
+        }
+        expect(component_helper.all_attributes).to eql(expected)
+      end
+
+      it "accepts integer numbers" do
+        component_helper = GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: -984_347_284_732)
+        expected = {
+          tabindex: -984_347_284_732,
+        }
+        expect(component_helper.all_attributes).to eql(expected)
+      end
+
+      it "accepts 0" do
+        component_helper = GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: "0")
+        expected = {
+          tabindex: "0",
+        }
+        expect(component_helper.all_attributes).to eql(expected)
+      end
+
+      it "does not accept text before a number" do
+        error = "tabindex_attribute attribute (abc1) is not recognised"
+        expect {
+          GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: "abc1")
+        }.to raise_error(ArgumentError, error)
+      end
+
+      it "does not accept text after a number" do
+        error = "tabindex_attribute attribute (123abc) is not recognised"
+        expect {
+          GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: "123abc")
+        }.to raise_error(ArgumentError, error)
+      end
+
+      it "does not accept extra negative symbols" do
+        error = "tabindex_attribute attribute (--1) is not recognised"
+        expect {
+          GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: "--1")
+        }.to raise_error(ArgumentError, error)
+      end
+
+      it "does not accept extra symbols" do
+        error = "tabindex_attribute attribute (-1!???) is not recognised"
+        expect {
+          GovukPublishingComponents::Presenters::ComponentWrapperHelper.new(tabindex: "-1!???")
+        }.to raise_error(ArgumentError, error)
+      end
+    end
   end
 end