Accept d3.selection object for bindto - #715

c3.js

@@ -151,7 +151,7 @@
         if ($$.initBrush) { $$.initBrush(); }
         if ($$.initZoom) { $$.initZoom(); }
 
-        $$.selectChart = d3.select(config.bindto);
+        $$.selectChart = typeof config.bindto.node === 'function' ? config.bindto : d3.select(config.bindto);
         if ($$.selectChart.empty()) {
             $$.selectChart = d3.select(document.createElement('div')).style('opacity', 0);
             $$.observeInserted($$.selectChart);

spec/core-spec.js

@@ -56,4 +56,18 @@ describe('c3 chart', function () {
 
     });
 
+    describe('bindto', function () {
+
+        it('should accept d3.selection object', function () {
+            args.bindto = d3.select('#chart');
+            expect(true).toBeTruthy();
+        });
+
+        it('should be created', function () {
+            var svg = d3.select('#chart svg');
+            expect(svg).not.toBeNull();
+        });
+
+    });
+
 });

src/core.js

@@ -146,7 +146,7 @@ c3_chart_internal_fn.initWithData = function (data) {
     if ($$.initBrush) { $$.initBrush(); }
     if ($$.initZoom) { $$.initZoom(); }
 
-    $$.selectChart = d3.select(config.bindto);
+    $$.selectChart = typeof config.bindto.node === 'function' ? config.bindto : d3.select(config.bindto);
     if ($$.selectChart.empty()) {
         $$.selectChart = d3.select(document.createElement('div')).style('opacity', 0);
         $$.observeInserted($$.selectChart);