From 8303f4b05e26bd066e3f60ec4d7271de6cfec721 Mon Sep 17 00:00:00 2001
From: Jukka Kurkela <jukka.kurkela@gmail.com>
Date: Thu, 16 Jan 2020 12:29:51 +0200
Subject: [PATCH] Conditionally use binarySearch for intersect mode

---
 src/core/core.datasetController.js |  4 +++
 src/core/core.interaction.js       | 49 ++++++++++++++----------------
 2 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/src/core/core.datasetController.js b/src/core/core.datasetController.js
index b0a63f02f48..8a46410d906 100644
--- a/src/core/core.datasetController.js
+++ b/src/core/core.datasetController.js
@@ -980,6 +980,10 @@ helpers.extend(DatasetController.prototype, {
 	 * @private
 	 */
 	_getSharedOptions: function(mode, el, options) {
+		if (!mode) {
+			// store element option sharing status for usage in interactions
+			this._elementsShareOptions = options && options.$shared;
+		}
 		if (mode !== 'reset' && options && options.$shared && el && el.options && el.options.$shared) {
 			return {target: el.options, options};
 		}
diff --git a/src/core/core.interaction.js b/src/core/core.interaction.js
index 05c1382983f..4d0ee5610cb 100644
--- a/src/core/core.interaction.js
+++ b/src/core/core.interaction.js
@@ -41,36 +41,38 @@ function evaluateAllVisibleItems(chart, handler) {
 	}
 }
 
+function useBinarySearch(axis, controller, _sorted, intersect) {
+	const iScale = controller._cachedMeta.iScale;
+	return iScale && axis === iScale.axis && _sorted &&
+		(!intersect || controller._elementsShareOptions);
+}
+
 /**
  * Helper function to get items using binary search, when the data is sorted.
  * @param {Chart} chart - the chart
  * @param {string} axis - the axis mode. x|y|xy
  * @param {object} position - the point to be nearest to
  * @param {function} handler - the callback to execute for each visible item
- * @return whether all scales were of a suitable type
+ * @param {boolean} intersect - consider intersecting items
  */
-function binarySearchItems(chart, axis, position, handler) {
+function optimizedEvaluateItems(chart, axis, position, handler, intersect) {
 	const metasets = chart._getSortedVisibleDatasetMetas();
 	for (let i = 0, ilen = metasets.length; i < ilen; ++i) {
-		const metaset = metasets[i];
-		const iScale = metaset.controller._cachedMeta.iScale;
-		if (!iScale || axis !== iScale.axis || !metaset._sorted) {
-			return false;
-		}
-	}
-
-	// do this only after checking whether all scales are of a suitable type
-	for (let i = 0, ilen = metasets.length; i < ilen; ++i) {
-		const {index, data} = metasets[i];
-		const {lo, hi, loIndex, hiIndex} = _lookup(data, axis, position[axis]);
-		if (lo) {
-			handler(lo, index, loIndex);
+		const {controller, data, index, _sorted} = metasets[i];
+		let startIndex = 0;
+		let endIndex = data.length - 1;
+		if (useBinarySearch(axis, controller, _sorted, intersect)) {
+			const {loIndex, hiIndex} = _lookup(data, axis, position[axis]);
+			startIndex = loIndex === null ? hiIndex : loIndex;
+			endIndex = hiIndex === null ? loIndex : hiIndex;
 		}
-		if (hi) {
-			handler(hi, index, hiIndex);
+		for (let j = startIndex; j <= endIndex; ++j) {
+			const element = data[j];
+			if (!element.skip) {
+				handler(element, index, j);
+			}
 		}
 	}
-	return true;
 }
 
 /**
@@ -96,7 +98,7 @@ function getDistanceMetricForAxis(axis) {
  * @param {string} axis - the axis mode. x|y|xy
  * @return {ChartElement[]} the nearest items
  */
-function getIntersectItems(chart, position) {
+function getIntersectItems(chart, position, axis) {
 	const items = [];
 
 	if (!_isPointInArea(position, chart.chartArea)) {
@@ -109,7 +111,7 @@ function getIntersectItems(chart, position) {
 		}
 	};
 
-	evaluateAllVisibleItems(chart, evaluationFunc);
+	optimizedEvaluateItems(chart, axis, position, evaluationFunc, true);
 	return items;
 }
 
@@ -146,12 +148,7 @@ function getNearestItems(chart, position, axis, intersect) {
 		}
 	};
 
-	const optimized = binarySearchItems(chart, axis, position, evaluationFunc);
-	if (optimized) {
-		return items;
-	}
-
-	evaluateAllVisibleItems(chart, evaluationFunc);
+	optimizedEvaluateItems(chart, axis, position, evaluationFunc);
 	return items;
 }