Add data.axes API

c3.js

@@ -6136,6 +6136,15 @@
         $$.redraw({withLegend: true});
         return config.data_colors;
     };
+    c3_chart_fn.data.axes = function (axes) {
+        var $$ = this.internal, config = $$.config;
+        if (!arguments.length) { return config.data_axes; }
+        Object.keys(axes).forEach(function (id) {
+            config.data_axes[id] = axes[id];
+        });
+        $$.redraw({withLegend: true});
+        return config.data_axes;
+    };
 
     c3_chart_fn.category = function (i, category) {
         var $$ = this.internal, config = $$.config;

spec/api.data-spec.js

@@ -12,8 +12,17 @@ describe('c3 api data', function () {
         data: {
             columns: [
                 ['data1', 30, 200, 100, 400, 150, 250],
-                ['data2', 50, 20, 10, 40, 15, 25]
-            ]
+                ['data2', 5000, 2000, 1000, 4000, 1500, 2500]
+            ],
+            axes: {
+                data1: 'y',
+                data2: 'y2'
+            }
+        },
+        axis: {
+            y2: {
+                show: true
+            }
         }
     };
 
@@ -69,4 +78,27 @@ describe('c3 api data', function () {
 
     });
 
+    describe('data.axes()', function () {
+
+        it('should return data.axes specified as argument', function () {
+            var results = chart.data.axes();
+            expect(results.data1).toBe('y');
+            expect(results.data2).toBe('y2');
+            expect(d3.select('.c3-axis-y g.tick text').text()).toBe('0');
+            expect(d3.select('.c3-axis-y2 g.tick text').text()).toBe('1000');
+        });
+
+        it('should return data.axes specified as api', function () {
+            var results = chart.data.axes({
+                data1: 'y2',
+                data2: 'y'
+            });
+            expect(results.data1).toBe('y2');
+            expect(results.data2).toBe('y');
+            expect(d3.select('.c3-axis-y g.tick text').text()).toBe('1000');
+            expect(d3.select('.c3-axis-y2 g.tick text').text()).toBe('0');
+        });
+
+    });
+
 });

src/api.data.js

@@ -29,3 +29,12 @@ c3_chart_fn.data.colors = function (colors) {
     $$.redraw({withLegend: true});
     return config.data_colors;
 };
+c3_chart_fn.data.axes = function (axes) {
+    var $$ = this.internal, config = $$.config;
+    if (!arguments.length) { return config.data_axes; }
+    Object.keys(axes).forEach(function (id) {
+        config.data_axes[id] = axes[id];
+    });
+    $$.redraw({withLegend: true});
+    return config.data_axes;
+};