From c32fa331da6a6d6213e52f35dc4cb8f9272275f8 Mon Sep 17 00:00:00 2001
From: kurkle <jukka.kurkela@gmail.com>
Date: Wed, 18 Sep 2019 11:08:47 +0300
Subject: [PATCH] Hover styling for dataset in 'dataset' mode

---
 src/controllers/controller.line.js | 15 +++++++++++++++
 src/core/core.controller.js        |  5 +++++
 src/core/core.datasetController.js |  6 ++++++
 3 files changed, 26 insertions(+)

diff --git a/src/controllers/controller.line.js b/src/controllers/controller.line.js
index c2d67549bfa..da22a705b04 100644
--- a/src/controllers/controller.line.js
+++ b/src/controllers/controller.line.js
@@ -315,4 +315,19 @@ module.exports = DatasetController.extend({
 		model.borderWidth = valueOrDefault(options.hoverBorderWidth, options.borderWidth);
 		model.radius = valueOrDefault(options.hoverRadius, options.radius);
 	},
+
+	setDatasetHoverStyle: function() {
+		var line = this.getMeta().dataset;
+		var model = line._model;
+		var config = this._config;
+		var getHoverColor = helpers.getHoverColor;
+
+		line.$previousStyle = {
+			backgroundColor: model.backgroundColor,
+			borderColor: model.borderColor
+		};
+
+		model.backgroundColor = valueOrDefault(config.hoverBackgroundColor, getHoverColor(config.backgroundColor));
+		model.borderColor = valueOrDefault(config.hoverBorderColor, getHoverColor(config.borderColor));
+	},
 });
diff --git a/src/core/core.controller.js b/src/core/core.controller.js
index 694e7764611..6f3f7f8d1b4 100644
--- a/src/core/core.controller.js
+++ b/src/core/core.controller.js
@@ -964,6 +964,11 @@ helpers.extend(Chart.prototype, /** @lends Chart */ {
 				this.getDatasetMeta(element._datasetIndex).controller[method](element);
 			}
 		}
+
+		if (mode === 'dataset') {
+			method = enabled ? 'setDatasetHoverStyle' : 'removeDatasetHoverStyle';
+			this.getDatasetMeta(elements[0]._datasetIndex).controller[method]();
+		}
 	},
 
 	/**
diff --git a/src/core/core.datasetController.js b/src/core/core.datasetController.js
index 03a249a3fde..129b2a71b17 100644
--- a/src/core/core.datasetController.js
+++ b/src/core/core.datasetController.js
@@ -453,6 +453,12 @@ helpers.extend(DatasetController.prototype, {
 		model.borderWidth = resolve([custom.hoverBorderWidth, dataset.hoverBorderWidth, model.borderWidth], undefined, index);
 	},
 
+	removeDatasetHoverStyle: function() {
+		this.removeHoverStyle(this.getMeta().dataset);
+	},
+
+	setDatasetHoverStyle: helpers.noop,
+
 	/**
 	 * @private
 	 */