Fix: Bar chart with indexAxis: 'y' requires data.labels (whereas 'x' …

…does not) (chartjs#11684)

src/core/core.config.js

@@ -132,6 +132,11 @@ function initConfig(config) {
 
   initOptions(config);
 
+  if (config.options.indexAxis === 'y' && config.data.labels.length === 0) {
+    config.data.labels = Object.keys(config.data.datasets[0].data);
+    config.data.datasets[0].data = Object.values(config.data.datasets[0].data);
+  }
+
   return config;
 }
 

test/fixtures/controller.bar/bar-indexAxis-y.js

@@ -0,0 +1,20 @@
+module.exports = {
+  config: {
+    type: 'bar',
+    data: {
+      datasets: [{
+        label: '# of Votes',
+        data: {a: 1, b: 3, c: 2}
+      }]
+    },
+    options: {
+      indexAxis: 'y'
+    }
+  },
+  options: {
+    canvas: {
+      height: 256,
+      width: 512
+    }
+  }
+};

test/specs/controller.bar.tests.js

@@ -1721,4 +1721,23 @@ describe('Chart.controllers.bar', function() {
       after: []
     }]);
   });
+
+  it('should treat and render indexAxis y as indexAxis x can without setting data labels', function() {
+    const chart = window.acquireChart({
+      type: 'bar',
+      data: {
+        datasets: [
+          {
+            label: '# of Votes',
+            data: {a: 1, b: 3, c: 2},
+          },
+        ],
+      },
+      options: {
+        indexAxis: 'y',
+      },
+    });
+
+    expect(chart.data.labels.length).toBe(3);
+  });
 });