Cache animations

Author: kurkle

src/core/core.config.js

@@ -248,7 +248,7 @@ export default class Config {
 	 */
 	createResolver(scopes, context, prefixes = ['']) {
 		const resolver = _createResolver(scopes, prefixes);
-		return context
+		return context && needContext(resolver, Object.getOwnPropertyNames(resolver))
 			? _attachContext(resolver, isFunction(context) ? context() : context)
 			: resolver;
 	}

src/core/core.datasetController.js

@@ -793,6 +793,12 @@ export default class DatasetController {
 	_resolveAnimations(index, mode, active) {
 		const me = this;
 		const chart = me.chart;
+		const cache = me._cachedDataOpts;
+		const cacheKey = 'animation-' + mode;
+		const cached = cache[cacheKey];
+		if (cached) {
+			return cached;
+		}
 		let options;
 		if (chart.options.animation !== false) {
 			const config = me.chart.config;
@@ -801,7 +807,11 @@ export default class DatasetController {
 			const context = () => me.getContext(index, active, mode);
 			options = config.createResolver(scopes, context);
 		}
-		return new Animations(chart, options && options[mode] || options);
+		const animations = new Animations(chart, options && options[mode] || options);
+		if (options._cacheable) {
+			cache[cacheKey] = animations && Object.freeze(animations);
+		}
+		return animations;
 	}
 
 	/**

src/helpers/helpers.config.js

@@ -10,6 +10,7 @@ import {defined, isArray, isFunction, isObject, resolveObjectKey, _capitalize} f
 export function _createResolver(scopes, prefixes = ['']) {
 	const cache = {
 		[Symbol.toStringTag]: 'Object',
+		_cacheable: true,
 		_scopes: scopes
 	};
 	return new Proxy(cache, {
@@ -42,6 +43,7 @@ export function _createResolver(scopes, prefixes = ['']) {
  */
 export function _attachContext(proxy, context, subProxy) {
 	const cache = {
+		_cacheable: false,
 		_proxy: proxy,
 		_context: context,
 		_subProxy: subProxy,