feat(plugin-vercel-analytics): add new vercel analytics plugin (#9687)

Co-authored-by: sebastien <lorber.sebastien@gmail.com>

packages/docusaurus-plugin-vercel-analytics/src/options.ts

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+import {DEFAULT_PLUGIN_ID} from '@docusaurus/utils';
+import logger from '@docusaurus/logger';
+import {Joi} from '@docusaurus/utils-validation';
+import type {OptionValidationContext} from '@docusaurus/types';
+
+export type PluginOptions = {
+  id: string;
+  mode: 'auto' | 'production' | 'development' | undefined;
+  debug: boolean | undefined;
+};
+
+export type Options = Partial<PluginOptions>;
+
+const pluginOptionsSchema = Joi.object<PluginOptions>({
+  mode: Joi.string().valid('auto', 'production', 'development').optional(),
+  debug: Joi.boolean().optional(),
+});
+
+// We can't validate this through the schema
+// Docusaurus core auto registers the id field to the schema already
+function ensureNoMultiInstance(options: Options) {
+  if (options?.id && options.id !== DEFAULT_PLUGIN_ID) {
+    throw new Error(
+      logger.interpolate`You site uses the Vercel Analytics plugin with a custom plugin id (name=${options.id}).
+      But this plugin is only supposed to be used at most once per site. Therefore providing a custom plugin id is unsupported.`,
+    );
+  }
+}
+
+export function validateOptions({
+  validate,
+  options,
+}: OptionValidationContext<Options, PluginOptions>): PluginOptions {
+  ensureNoMultiInstance(options);
+  return validate(pluginOptionsSchema, options);
+}