PluginService as ES6 class (#7075)

* PluginService as ES6 class
* Review update

diff --git a/src/core/core.plugins.js b/src/core/core.plugins.js
index f5522fd1512e86497a96498afae3c3109659fb2d..66cb1be952772d0d13b2194770fbfcf95d6d2e54 100644 (file)
--- a/src/core/core.plugins.js
+++ b/src/core/core.plugins.js
@@ -22,26 +22,28 @@ defaults._set('plugins', {});
  * @namespace Chart.plugins
  * @since 2.1.0
  */
-export default {
-       /**
-        * Globally registered plugins.
-        * @private
-        */
-       _plugins: [],
+class PluginService {
+       constructor() {
+               /**
+                * Globally registered plugins.
+                * @private
+                */
+               this._plugins = [];
 
-       /**
-        * This identifier is used to invalidate the descriptors cache attached to each chart
-        * when a global plugin is registered or unregistered. In this case, the cache ID is
-        * incremented and descriptors are regenerated during following API calls.
-        * @private
-        */
-       _cacheId: 0,
+               /**
+                * This identifier is used to invalidate the descriptors cache attached to each chart
+                * when a global plugin is registered or unregistered. In this case, the cache ID is
+                * incremented and descriptors are regenerated during following API calls.
+                * @private
+                */
+               this._cacheId = 0;
+       }
 
        /**
         * Registers the given plugin(s) if not already registered.
         * @param {IPlugin[]|IPlugin} plugins plugin instance(s).
         */
-       register: function(plugins) {
+       register(plugins) {
                var p = this._plugins;
                ([]).concat(plugins).forEach(function(plugin) {
                        if (p.indexOf(plugin) === -1) {
@@ -50,13 +52,13 @@ export default {
                });
 
                this._cacheId++;
-       },
+       }
 
        /**
         * Unregisters the given plugin(s) only if registered.
         * @param {IPlugin[]|IPlugin} plugins plugin instance(s).
         */
-       unregister: function(plugins) {
+       unregister(plugins) {
                var p = this._plugins;
                ([]).concat(plugins).forEach(function(plugin) {
                        var idx = p.indexOf(plugin);
@@ -66,34 +68,34 @@ export default {
                });
 
                this._cacheId++;
-       },
+       }
 
        /**
         * Remove all registered plugins.
         * @since 2.1.5
         */
-       clear: function() {
+       clear() {
                this._plugins = [];
                this._cacheId++;
-       },
+       }
 
        /**
         * Returns the number of registered plugins?
         * @returns {number}
         * @since 2.1.5
         */
-       count: function() {
+       count() {
                return this._plugins.length;
-       },
+       }
 
        /**
         * Returns all registered plugin instances.
         * @returns {IPlugin[]} array of plugin objects.
         * @since 2.1.5
         */
-       getAll: function() {
+       getAll() {
                return this._plugins;
-       },
+       }
 
        /**
         * Calls enabled plugins for `chart` on the specified hook and with the given args.
@@ -104,7 +106,7 @@ export default {
         * @param {Array} [args] - Extra arguments to apply to the hook call.
         * @returns {boolean} false if any of the plugins return false, else returns true.
         */
-       notify: function(chart, hook, args) {
+       notify(chart, hook, args) {
                var descriptors = this.descriptors(chart);
                var ilen = descriptors.length;
                var i, descriptor, plugin, params, method;
@@ -123,14 +125,14 @@ export default {
                }
 
                return true;
-       },
+       }
 
        /**
         * Returns descriptors of enabled plugins for the given chart.
         * @returns {object[]} [{ plugin, options }]
         * @private
         */
-       descriptors: function(chart) {
+       descriptors(chart) {
                var cache = chart.$plugins || (chart.$plugins = {});
                if (cache.id === this._cacheId) {
                        return cache.descriptors;
@@ -167,7 +169,7 @@ export default {
                cache.descriptors = descriptors;
                cache.id = this._cacheId;
                return descriptors;
-       },
+       }
 
        /**
         * Invalidates cache for the given chart: descriptors hold a reference on plugin option,
@@ -175,10 +177,13 @@ export default {
         * https://github.com/chartjs/Chart.js/issues/5111#issuecomment-355934167
         * @private
         */
-       _invalidate: function(chart) {
+       _invalidate(chart) {
                delete chart.$plugins;
        }
-};
+}
+
+// singleton instance
+export default new PluginService();
 
 /**
  * Plugin extension hooks.