Add bar/column chart option

- can display a bar or column chart instead of a line chart
- also add explicit documentation for the hide_legend option, which seemed to be missing
- not sure if it's possible to write a test for this, as the option is passed to the component, which then calls the chart, so there's no measurable difference in outcome, other than visually within the elements created by the chart JS

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

@@ -10,6 +10,7 @@
   rows ||= []
   keys ||= []
   chart_overview ||= nil
+  chart_type ||= "line"
   minimal ||= false
   hide_heading ||= minimal
   hide_legend ||= minimal
@@ -64,7 +65,13 @@
         </span>
       <% end %>
 
-      <%= line_chart(chart_helper.chart_format_data, library: chart_helper.chart_options) %>
+      <% if chart_type == "column" %>
+        <%= column_chart(chart_helper.chart_format_data, library: chart_helper.chart_options) %>
+      <% elsif chart_type == "bar" %>
+        <%= bar_chart(chart_helper.chart_format_data, library: chart_helper.chart_options) %>
+      <% else %>
+        <%= line_chart(chart_helper.chart_format_data, library: chart_helper.chart_options) %>
+      <% end %>
     <% end %>
 
     <% unless minimal %>

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

@@ -22,7 +22,6 @@ examples:
       h_axis_title: Day
       v_axis_title: Views
       chart_overview: This chart shows page views for January 2015.
-      hide_legend: true
       keys:
         - "2015-01-01"
         - "2015-01-02"
@@ -102,6 +101,77 @@ examples:
             - 27
             - 18
             - 34
+  hide_legend:
+    data:
+      chart_heading: Page views chart
+      h_axis_title: Day
+      v_axis_title: Views
+      chart_overview: This chart shows page views for January 2015.
+      hide_legend: true
+      keys:
+        - "2015-01-01"
+        - "2015-01-02"
+        - "2015-01-03"
+        - "2015-01-04"
+        - "2015-01-05"
+        - "2015-01-06"
+        - "2015-01-07"
+        - "2015-01-08"
+        - "2015-01-09"
+        - "2015-01-10"
+      rows:
+        - label: January 2015
+          values:
+            - 500
+            - 1190
+            - 740
+            - 820
+            - 270
+            - 450
+            - 110
+            - 210
+            - 670
+            - 430
+  bar_chart:
+    data:
+      chart_heading: Hats owned
+      h_axis_title: Day
+      v_axis_title: Views
+      chart_overview: This chart shows page views for January 2015.
+      chart_type: "bar"
+      hide_legend: true
+      keys:
+        - Jon
+        - Ash
+        - James
+        - Phil
+      rows:
+        - label: Hats owned
+          values:
+            - 3
+            - 1
+            - 1
+            - 2
+  column_chart:
+    data:
+      chart_heading: Hats owned
+      h_axis_title: Day
+      v_axis_title: Views
+      chart_overview: This chart shows page views for January 2015.
+      chart_type: "column"
+      hide_legend: true
+      keys:
+        - Jon
+        - Ash
+        - James
+        - Phil
+      rows:
+        - label: Hats owned
+          values:
+            - 3
+            - 1
+            - 1
+            - 2
   vertical table:
     description: Reorient the table to better suit the output of some data sets.
     data: