Add chart data property setter and unit tests

Chart data can now be entirely replaced using `chart.data = {...}` thanks to the new property setter (instead of using `chart.config.data = {}`). Also update the documentation, as suggested by @ldaguise and @kennethkalmer, with a note about versions prior 2.6.

docs/09-Advanced.md

@@ -25,7 +25,7 @@ myLineChart.destroy();
 
 #### .update(duration, lazy)
 
-Triggers an update of the chart. This can be safely called after replacing the entire data object. This will update all scales, legends, and then re-render the chart.
+Triggers an update of the chart. This can be safely called after updating the data object. This will update all scales, legends, and then re-render the chart.
 
 ```javascript
 // duration is the time for the animation of the redraw in milliseconds
@@ -34,6 +34,8 @@ myLineChart.data.datasets[0].data[2] = 50; // Would update the first dataset's v
 myLineChart.update(); // Calling update now animates the position of March from 90 to 50.
 ```
 
+> **Note:** replacing the data reference (e.g. `myLineChart.data = {datasets: [...]}` only works starting **version 2.6**. Prior that, replacing the entire data object could be achieved with the following workaround: `myLineChart.config.data = {datasets: [...]}`.
+
 #### .reset()
 
 Reset the chart to it's state before the initial animation. A new animation can then be triggered using `update`.

src/core/core.controller.js

@@ -98,9 +98,13 @@ module.exports = function(Chart) {
 			// Add the chart instance to the global namespace
 			Chart.instances[me.id] = me;
 
+			// Define alias to the config data: `chart.data === chart.config.data`
 			Object.defineProperty(me, 'data', {
 				get: function() {
 					return me.config.data;
+				},
+				set: function(value) {
+					me.config.data = value;
 				}
 			});
 

test/controller.bar.tests.js

@@ -738,8 +738,8 @@ describe('Bar controller tests', function() {
 			expect(meta.data[i]._model.base).toBeCloseToPixel(484);
 			expect(meta.data[i]._model.width).toBeCloseToPixel(40);
 			expect(meta.data[i]._model).toEqual(jasmine.objectContaining({
-				datasetLabel: chart.config.data.datasets[1].label,
-				label: chart.config.data.labels[i],
+				datasetLabel: chart.data.datasets[1].label,
+				label: chart.data.labels[i],
 				backgroundColor: 'red',
 				borderSkipped: 'top',
 				borderColor: 'blue',

test/core.controller.tests.js

@@ -57,6 +57,25 @@ describe('Chart', function() {
 			expect(chart.data.datasets[1].data).toBe(ds1.data);
 		});
 
+		it('should define chart.data as an alias for config.data', function() {
+			var config = {data: {labels: [], datasets: []}};
+			var chart = acquireChart(config);
+
+			expect(chart.data).toBe(config.data);
+
+			chart.data = {labels: [1, 2, 3], datasets: [{data: [4, 5, 6]}]};
+
+			expect(config.data).toBe(chart.data);
+			expect(config.data.labels).toEqual([1, 2, 3]);
+			expect(config.data.datasets[0].data).toEqual([4, 5, 6]);
+
+			config.data = {labels: [7, 8, 9], datasets: [{data: [10, 11, 12]}]};
+
+			expect(chart.data).toBe(config.data);
+			expect(chart.data.labels).toEqual([7, 8, 9]);
+			expect(chart.data.datasets[0].data).toEqual([10, 11, 12]);
+		});
+
 		it('should initialize config with default options', function() {
 			var callback = function() {};
 

test/core.tooltip.tests.js

@@ -692,10 +692,10 @@ describe('Core.Tooltip', function() {
 		expect(tooltip._view.dataPoints[0].index).toEqual(pointIndex);
 		expect(tooltip._view.dataPoints[0].datasetIndex).toEqual(datasetIndex);
 		expect(tooltip._view.dataPoints[0].xLabel).toEqual(
-			chart.config.data.labels[pointIndex]
+			chart.data.labels[pointIndex]
 		);
 		expect(tooltip._view.dataPoints[0].yLabel).toEqual(
-			chart.config.data.datasets[datasetIndex].data[pointIndex]
+			chart.data.datasets[datasetIndex].data[pointIndex]
 		);
 		expect(tooltip._view.dataPoints[0].x).toBeCloseToPixel(point._model.x);
 		expect(tooltip._view.dataPoints[0].y).toBeCloseToPixel(point._model.y);