docs: add new faq docs

website/docs/faq/docs.js

@@ -16,4 +16,12 @@ exports.docs = [
     title: 'Why is a background fill not working?',
     slug: '/faq/fill-property',
   },
+  {
+    title: 'How to fix "... is not a registered element" error?',
+    slug: '/faq/registered-element',
+  },
+  {
+    title: 'How to fix "... is not a registered scale" error?',
+    slug: '/faq/registered-scale',
+  },
 ];

website/docs/faq/registered-element.md

@@ -0,0 +1,19 @@
+---
+slug: /faq/registered-element
+---
+
+# How to fix "... is not a registered element" error?
+
+As you can see in [migration to v4 guide](/docs/migration-to-v4#tree-shaking):
+
+> v4 of this library, [just like Chart.js v3](https://www.chartjs.org/docs/latest/getting-started/v3-migration.html#setup-and-installation), is tree-shakable. It means that you need to import and register the controllers, elements, scales, and plugins you want to use.
+>
+> For a list of all the available items to import, see [Chart.js docs](https://www.chartjs.org/docs/latest/getting-started/integration.html#bundlers-webpack-rollup-etc).
+
+So you should register missed components. For example, if you have `Uncaught Error: "arc" is not a registered element.` error, you should register `ArcElement`:
+
+```js
+import { ArcElement } from "chart.js";
+
+ChartJS.register(ArcElement);
+```

website/docs/faq/registered-scale.md

@@ -0,0 +1,19 @@
+---
+slug: /faq/registered-scale
+---
+
+# How to fix "... is not a registered scale" error?
+
+As you can see in [migration to v4 guide](/docs/migration-to-v4#tree-shaking):
+
+> v4 of this library, [just like Chart.js v3](https://www.chartjs.org/docs/latest/getting-started/v3-migration.html#setup-and-installation), is tree-shakable. It means that you need to import and register the controllers, elements, scales, and plugins you want to use.
+>
+> For a list of all the available items to import, see [Chart.js docs](https://www.chartjs.org/docs/latest/getting-started/integration.html#bundlers-webpack-rollup-etc).
+
+So you should register missed components. For example, if you have `Uncaught Error: "category" is not a registered scale.` error, you should register `CategoryScale`:
+
+```js
+import { CategoryScale } from "chart.js";
+
+ChartJS.register(CategoryScale);
+```