add toggle between issue count and issue weight

app/assets/javascripts/burndown_chart/index.js

@@ -17,10 +17,32 @@ $(() => {
     const startDate = chartElm.data('startDate');
     const dueDate = chartElm.data('endDate');
     const chartData = chartElm.data('chartData');
+    const openIssuesCount = chartData.map(d => [d[0], d[1]]);
+    const openIssuesWeight = chartData.map(d => [d[0], d[2]]);
 
     const chart = new BurndownChart({ container, startDate, dueDate });
 
-    chart.setData(chartData, { label: 'Open Issues', animate: true });
+    let currentView = 'count';
+    chart.setData(openIssuesCount, { label: 'Open Issues', animate: true });
+
+    $('.burndown-header').on('click', '.btn', function switchData() {
+      const $this = $(this);
+      const show = $this.data('show');
+      if (currentView !== show) {
+        currentView = show;
+        $this.addClass('active').siblings().removeClass('active');
+        switch (show) {
+          case 'count':
+            chart.setData(openIssuesCount, { label: 'Open Issues', animate: true });
+            break;
+          case 'weight':
+            chart.setData(openIssuesWeight, { label: 'Open Issue Weight', animate: true });
+            break;
+          default:
+            break;
+        }
+      }
+    });
 
     window.addEventListener('resize', () => chart.animateResize(1));
     $(document).on('click', '.js-sidebar-toggle', () => chart.animateResize(2));

app/views/shared/milestones/_burndown.html.haml

@@ -25,5 +25,10 @@
 - if can_generate_chart
   .burndown-header
     %h3
-      Open issues
+      Burndown Chart
+      .btn-group
+        %button.btn.btn-xs.btn-primary.active{ data: { show: 'count' } }
+          Issues
+        %button.btn.btn-xs.btn-primary{ data: { show: 'weight' } }
+          Issue Weight
   .burndown-chart{ data: { start_date: burndown.start_date.strftime("%Y-%m-%d"), end_date: burndown.end_date.strftime("%Y-%m-%d"), chart_data: burndown.chart_data.to_json } }