Fix tooltip title to be formatted

c3.js

@@ -128,8 +128,8 @@
 
         // tooltip - show when mouseover on each data
         var __tooltip_contents = getConfig(['tooltip', 'contents'], function (d) {
-            var date = isTimeSeries ? d[0].x.getFullYear() + '.' + (d[0].x.getMonth() + 1) + '.' + d[0].x.getDate() : isCategorized ? category(d[0].x) : d[0].x,
-                text = "<table class='-tooltip'><tr><th colspan='2'>" + date + "</th></tr>", i, value, name;
+            var title = getXAxisTickFormat()(d[0].x),
+                text = "<table class='-tooltip'><tr><th colspan='2'>" + title + "</th></tr>", i, value, name;
             for (i = 0; i < d.length; i++) {
                 if (isDefined(d[i])) {
                     value = isDefined(d[i].value) ? (Math.round(d[i].value * 100) / 100).toFixed(2) : '-';
@@ -329,13 +329,9 @@
 
         function getXAxis(scale, orient) {
             var axis = (isCategorized ? categoryAxis() : d3.svg.axis()).scale(scale).orient(orient);
-            var tickFormat = isTimeSeries ? defaultTimeFormat : null;
 
             // Set tick format
-            if (__axis_x_tick_format) {
-                tickFormat = typeof __axis_x_tick_format === 'function' ? __axis_x_tick_format : isTimeSeries ? function (date) { return d3.time.format(__axis_x_tick_format)(date); } : null;
-            }
-            axis.tickFormat(tickFormat);
+            axis.tickFormat(getXAxisTickFormat());
 
             // Set categories
             if (isCategorized) {
@@ -353,6 +349,13 @@
         function getAxisId(id) {
             return id in __data_axes ? __data_axes[id] : 'y';
         }
+        function getXAxisTickFormat() {
+            var tickFormat = isTimeSeries ? defaultTimeFormat : isCategorized ? category : null;
+            if (__axis_x_tick_format) {
+                tickFormat = typeof __axis_x_tick_format === 'function' ? __axis_x_tick_format : isTimeSeries ? function (date) { return d3.time.format(__axis_x_tick_format)(date); } : tickFormat;
+            }
+            return tickFormat;
+        }
 
         //-- Domain --//