Implement per-dataset type (default and per-chart) options

docs/configuration/README.md

@@ -31,3 +31,40 @@ var chartDifferentHoverMode = new Chart(ctx, {
     }
 });
 ```
+
+## Dataset Configuration
+
+Options may be configured directly on the dataset. The dataset options can be changed at 3 different levels and are evaluated with the following priority:
+
+- per dataset: dataset.*
+- per chart: options.datasets[type].*
+- or globally: Chart.defaults.global.datasets[type].*
+
+where type corresponds to the dataset type.
+
+*Note:* dataset options take precedence over element options.
+
+The following example would set the `showLine` option to 'false' for all line datasets except for those overridden by options passed to the dataset on creation.
+
+```javascript
+// Do not show lines for all datasets by default
+Chart.defaults.global.datasets.line.showLine = false;
+
+// This chart would show a line only for the third dataset
+var chart = new Chart(ctx, {
+    type: 'line',
+    data: {
+        datasets: [{
+            data: [0, 0],
+        }, {
+            data: [0, 1]
+        }, {
+            data: [1, 0],
+            showLine: true // overrides the `line` dataset default
+        }, {
+            type: 'scatter', // 'line' dataset default does not affect this dataset since it's a 'scatter'
+            data: [1, 1]
+        }]
+    }
+});
+```

src/controllers/controller.bar.js

@@ -382,6 +382,7 @@ module.exports = DatasetController.extend({
 		var chart = me.chart;
 		var datasets = chart.data.datasets;
 		var dataset = datasets[me.index];
+		var datasetOpts = me._config;
 		var custom = rectangle.custom || {};
 		var options = chart.options.elements.rectangle;
 		var values = {};
@@ -406,7 +407,7 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[key],
+				datasetOpts[key],
 				options[key]
 			], context, index);
 		}

src/controllers/controller.bubble.js

@@ -127,6 +127,7 @@ module.exports = DatasetController.extend({
 		var chart = me.chart;
 		var datasets = chart.data.datasets;
 		var dataset = datasets[me.index];
+		var datasetOpts = me._config;
 		var custom = point.custom || {};
 		var options = chart.options.elements.point;
 		var data = dataset.data[index];
@@ -158,7 +159,7 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[key],
+				datasetOpts[key],
 				options[key]
 			], context, index);
 		}

src/controllers/controller.doughnut.js

@@ -305,7 +305,12 @@ module.exports = DatasetController.extend({
 
 		for (i = 0, ilen = arcs.length; i < ilen; ++i) {
 			arc = arcs[i];
-			options = controller ? controller._resolveElementOptions(arc, i) : arc._options;
+			if (controller) {
+				controller._configure();
+				options = controller._resolveElementOptions(arc, i);
+			} else {
+				options = arc._options;
+			}
 			if (options.borderAlign !== 'inner') {
 				borderWidth = options.borderWidth;
 				hoverWidth = options.hoverBorderWidth;
@@ -343,6 +348,7 @@ module.exports = DatasetController.extend({
 		var me = this;
 		var chart = me.chart;
 		var dataset = me.getDataset();
+		var datasetOpts = me._config;
 		var custom = arc.custom || {};
 		var options = chart.options.elements.arc;
 		var values = {};
@@ -370,7 +376,7 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[key],
+				datasetOpts[key],
 				options[key]
 			], context, index);
 		}

src/controllers/controller.line.js

@@ -29,10 +29,6 @@ defaults._set('line', {
 	}
 });
 
-function lineEnabled(dataset, options) {
-	return valueOrDefault(dataset.showLine, options.showLines);
-}
-
 module.exports = DatasetController.extend({
 
 	datasetElementType: elements.Line,
@@ -44,9 +40,10 @@ module.exports = DatasetController.extend({
 		var meta = me.getMeta();
 		var line = meta.dataset;
 		var points = meta.data || [];
+		var options = me.chart.options;
 		var scale = me.getScaleForId(meta.yAxisID);
 		var dataset = me.getDataset();
-		var showLine = lineEnabled(dataset, me.chart.options);
+		var showLine = me._showLine = valueOrDefault(me._config.showLine, options.showLines);
 		var i, ilen;
 
 		// Update Line
@@ -132,6 +129,7 @@ module.exports = DatasetController.extend({
 		var me = this;
 		var chart = me.chart;
 		var dataset = chart.data.datasets[me.index];
+		var datasetOpts = me._config;
 		var custom = element.custom || {};
 		var options = chart.options.elements.point;
 		var values = {};
@@ -164,8 +162,8 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[ELEMENT_OPTIONS[key]],
-				dataset[key],
+				datasetOpts[ELEMENT_OPTIONS[key]],
+				datasetOpts[key],
 				options[key]
 			], context, index);
 		}
@@ -181,6 +179,7 @@ module.exports = DatasetController.extend({
 		var chart = me.chart;
 		var datasetIndex = me.index;
 		var dataset = chart.data.datasets[datasetIndex];
+		var datasetOpts = me._config;
 		var custom = element.custom || {};
 		var options = chart.options;
 		var elementOptions = options.elements.line;
@@ -210,17 +209,17 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[key],
+				datasetOpts[key],
 				elementOptions[key]
 			], context);
 		}
 
 		// The default behavior of lines is to break at null values, according
 		// to https://github.com/chartjs/Chart.js/issues/2435#issuecomment-216718158
 		// This option gives lines the ability to span gaps
-		values.spanGaps = valueOrDefault(dataset.spanGaps, options.spanGaps);
-		values.tension = valueOrDefault(dataset.lineTension, elementOptions.tension);
-		values.steppedLine = resolve([custom.steppedLine, dataset.steppedLine, elementOptions.stepped]);
+		values.spanGaps = valueOrDefault(datasetOpts.spanGaps, options.spanGaps);
+		values.tension = valueOrDefault(datasetOpts.lineTension, elementOptions.tension);
+		values.steppedLine = resolve([custom.steppedLine, datasetOpts.steppedLine, elementOptions.stepped]);
 
 		return values;
 	},
@@ -319,11 +318,11 @@ module.exports = DatasetController.extend({
 		var meta = me.getMeta();
 		var points = meta.data || [];
 		var area = chart.chartArea;
+		var i = 0;
 		var ilen = points.length;
 		var halfBorderWidth;
-		var i = 0;
 
-		if (lineEnabled(me.getDataset(), chart.options)) {
+		if (me._showLine) {
 			halfBorderWidth = (meta.dataset._model.borderWidth || 0) / 2;
 
 			helpers.canvas.clipArea(chart.ctx, {

src/controllers/controller.polarArea.js

@@ -248,6 +248,7 @@ module.exports = DatasetController.extend({
 		var me = this;
 		var chart = me.chart;
 		var dataset = me.getDataset();
+		var datasetOpts = me._config;
 		var custom = arc.custom || {};
 		var options = chart.options.elements.arc;
 		var values = {};
@@ -275,7 +276,7 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[key],
+				datasetOpts[key],
 				options[key]
 			], context, index);
 		}

src/controllers/controller.radar.js

@@ -109,6 +109,7 @@ module.exports = DatasetController.extend({
 		var me = this;
 		var chart = me.chart;
 		var dataset = chart.data.datasets[me.index];
+		var datasetOpts = me._config;
 		var custom = element.custom || {};
 		var options = chart.options.elements.point;
 		var values = {};
@@ -141,8 +142,8 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[ELEMENT_OPTIONS[key]],
-				dataset[key],
+				datasetOpts[ELEMENT_OPTIONS[key]],
+				datasetOpts[key],
 				options[key]
 			], context, index);
 		}
@@ -157,6 +158,7 @@ module.exports = DatasetController.extend({
 		var me = this;
 		var chart = me.chart;
 		var dataset = chart.data.datasets[me.index];
+		var datasetOpts = me._config;
 		var custom = element.custom || {};
 		var options = chart.options.elements.line;
 		var values = {};
@@ -177,7 +179,7 @@ module.exports = DatasetController.extend({
 			key = keys[i];
 			values[key] = resolve([
 				custom[key],
-				dataset[key],
+				datasetOpts[key],
 				options[key]
 			]);
 		}

src/controllers/controller.scatter.js

@@ -21,8 +21,6 @@ defaults._set('scatter', {
 		}]
 	},
 
-	showLines: false,
-
 	tooltips: {
 		callbacks: {
 			title: function() {
@@ -35,5 +33,13 @@ defaults._set('scatter', {
 	}
 });
 
+defaults._set('global', {
+	datasets: {
+		scatter: {
+			showLine: false
+		}
+	}
+});
+
 // Scatter charts use line controllers
 module.exports = LineController;

src/core/core.controller.js

@@ -567,7 +567,7 @@ helpers.extend(Chart.prototype, /** @lends Chart */ {
 			return;
 		}
 
-		meta.controller.update();
+		meta.controller._update();
 
 		plugins.notify(me, 'afterDatasetUpdate', [args]);
 	},

src/core/core.datasetController.js

@@ -100,6 +100,7 @@ helpers.extend(DatasetController.prototype, {
 		me.index = datasetIndex;
 		me.linkScales();
 		me.addElements();
+		me._type = me.getMeta().type;
 	},
 
 	updateIndex: function(datasetIndex) {
@@ -160,7 +161,7 @@ helpers.extend(DatasetController.prototype, {
 	},
 
 	reset: function() {
-		this.update(true);
+		this._update(true);
 	},
 
 	/**
@@ -236,6 +237,30 @@ helpers.extend(DatasetController.prototype, {
 		me.resyncElements();
 	},
 
+	/**
+	 * Returns the merged user-supplied and default dataset-level options
+	 * @private
+	 */
+	_configure: function() {
+		var me = this;
+		me._config = helpers.merge({}, [
+			me.chart.options.datasets[me._type],
+			me.getDataset(),
+		], {
+			merger: function(key, target, source) {
+				if (key !== '_meta' && key !== 'data') {
+					helpers._merger(key, target, source);
+				}
+			}
+		});
+	},
+
+	_update: function(reset) {
+		var me = this;
+		me._configure();
+		me.update(reset);
+	},
+
 	update: helpers.noop,
 
 	transition: function(easingValue) {

src/core/core.defaults.js

@@ -11,6 +11,8 @@ var defaults = {
 	}
 };
 
+// TODO(v3): remove 'global' from namespace.  all default are global and
+// there's inconsistency around which options are under 'global'
 defaults._set('global', {
 	defaultColor: 'rgba(0,0,0,0.1)',
 	defaultFontColor: '#666',