feat(chart.js): allow to access charts container (#41537)

This allows to access readonly container for charts from global
namespace required in some use-case scenarios.

Thanks!

types/chart.js/chart.js-tests.ts

@@ -302,6 +302,11 @@ const customTooltipsPieChart = new Chart(ctx, {
 // platform global values
 Chart.platform.disableCSSInjection = true;
 
+// Chart instances in the global namespace
+for (const id in Chart.instances) {
+    Chart.instances[id].resize();
+}
+
 // default global static values
 Chart.defaults.global.defaultFontColor = '#544615';
 Chart.defaults.global.defaultFontFamily = 'Arial';

types/chart.js/index.d.ts

@@ -77,6 +77,10 @@ declare class Chart {
 
     // Tooltip Static Options
     static Tooltip: Chart.ChartTooltipsStaticConfiguration;
+
+    static readonly instances: {
+        [key: string]: Chart;
+    };
 }
 declare class PluginServiceStatic {
     register(plugin: Chart.PluginServiceGlobalRegistration & Chart.PluginServiceRegistrationOptions): void;