From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Thu, 21 Nov 2019 12:20:18 +0000 (-0800)
Subject: Don't store _meta on dataset (#6778)
X-Git-Tag: v3.0.0-alpha~221
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ea903659720d89ad7bf83bf10cb1e7440dae012b;p=thirdparty%2FChart.js.git

Don't store _meta on dataset (#6778)
---

diff --git a/docs/getting-started/v3-migration.md b/docs/getting-started/v3-migration.md
index f803f5b3a..62c66750b 100644
--- a/docs/getting-started/v3-migration.md
+++ b/docs/getting-started/v3-migration.md
@@ -83,6 +83,7 @@ Chart.js 3.0 introduces a number of breaking changes. Chart.js 2.0 was released
 
 #### Removal of private APIs
 
+* `Chart.data.datasets[datasetIndex]._meta`
 * `Element._ctx`
 * `Element._model.datasetLabel`
 * `Element._model.label`
diff --git a/src/core/core.controller.js b/src/core/core.controller.js
index dee8ebc53..dd4202162 100644
--- a/src/core/core.controller.js
+++ b/src/core/core.controller.js
@@ -857,15 +857,13 @@ helpers.extend(Chart.prototype, /** @lends Chart */ {
 	},
 
 	getDatasetMeta: function(datasetIndex) {
-		var me = this;
-		var dataset = me.data.datasets[datasetIndex];
-		if (!dataset._meta) {
-			dataset._meta = {};
-		}
+		const me = this;
+		const dataset = me.data.datasets[datasetIndex];
+		const metasets = me._metasets = me._metasets || [];
+		let meta = metasets[datasetIndex];
 
-		var meta = dataset._meta[me.id];
 		if (!meta) {
-			meta = dataset._meta[me.id] = {
+			meta = metasets[datasetIndex] = {
 				type: null,
 				data: [],
 				dataset: null,
@@ -907,13 +905,12 @@ helpers.extend(Chart.prototype, /** @lends Chart */ {
 	 * @private
 	 */
 	destroyDatasetMeta: function(datasetIndex) {
-		var id = this.id;
-		var dataset = this.data.datasets[datasetIndex];
-		var meta = dataset._meta && dataset._meta[id];
+		const me = this;
+		const meta = me._metasets && me._metasets[datasetIndex];
 
 		if (meta) {
 			meta.controller.destroy();
-			delete dataset._meta[id];
+			delete me._metasets[datasetIndex];
 		}
 	},
 
diff --git a/src/core/core.datasetController.js b/src/core/core.datasetController.js
index 6e4ef71ce..e08d2000d 100644
--- a/src/core/core.datasetController.js
+++ b/src/core/core.datasetController.js
@@ -474,7 +474,7 @@ helpers.extend(DatasetController.prototype, {
 			me.getDataset(),
 		], {
 			merger: function(key, target, source) {
-				if (key !== '_meta' && key !== 'data') {
+				if (key !== 'data') {
 					helpers._merger(key, target, source);
 				}
 			}