algolia · sarahdayan · Oct 19, 2021 · Oct 15, 2021 · Oct 15, 2021 · Oct 15, 2021
diff --git a/.eslintrc.js b/.eslintrc.js
@@ -34,7 +34,7 @@ module.exports = {
     '@typescript-eslint/camelcase': [
       ERROR,
       {
-        allow: ['__autocomplete_'],
+        allow: ['__autocomplete_', 'aa_core', 'aa_js'],
       },
     ],
     // Useful to call functions like `nodeItem?.scrollIntoView()`.

diff --git a/bundlesize.config.json b/bundlesize.config.json
@@ -2,11 +2,11 @@
   "files": [
     {
       "path": "packages/autocomplete-core/dist/umd/index.production.js",
-      "maxSize": "5.5 kB"
+      "maxSize": "5.75 kB"
     },
     {
       "path": "packages/autocomplete-js/dist/umd/index.production.js",
-      "maxSize": "16 kB"
+      "maxSize": "16.25 kB"
     },
     {
       "path": "packages/autocomplete-preset-algolia/dist/umd/index.production.js",

diff --git a/packages/autocomplete-core/src/__tests__/metadata.test.ts b/packages/autocomplete-core/src/__tests__/metadata.test.ts
@@ -0,0 +1,169 @@
+import { createAlgoliaInsightsPlugin } from '@algolia/autocomplete-plugin-algolia-insights';
+import { noop, version } from '@algolia/autocomplete-shared';
+import insightsClient from 'search-insights';
+
+import { createPlayground, defer } from '../../../../test/utils';
+import { createAutocomplete } from '../createAutocomplete';
+
+beforeEach(() => {
+  document.head.innerHTML = '';
+});
+
+const algoliaCrawlerEnvironment = createEnvironmentWithUserAgent(
+  'Algolia Crawler 2.303.5'
+);
+
+describe('metadata', () => {
+  test('does not enable metadata with regular user agents', async () => {
+    createPlayground(createAutocomplete, {
+      environment: createEnvironmentWithUserAgent(
+        'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:93.0) Gecko/20100101 Firefox/93.0'
+      ),
+    });
+
+    await defer(noop, 0);
+
+    expect(document.head).toMatchInlineSnapshot(`<head />`);
+  });
+
+  test('does not enable metadata with no window', async () => {
+    createPlayground(createAutocomplete, {
+      environment: {},
+    });
+
+    await defer(noop, 0);
+
+    expect(document.head).toMatchInlineSnapshot(`<head />`);
+  });
+
+  test('enables metadata with Algolia Crawler user agents', async () => {
+    createPlayground(createAutocomplete, {
+      environment: algoliaCrawlerEnvironment,
+    });
+
+    await defer(noop, 0);
+
+    expect(
+      JSON.parse(
+        document.head.querySelector<HTMLMetaElement>(
+          'meta[name="algolia:metadata"]'
+        ).content
+      )
+    ).toEqual({
+      options: { 'autocomplete-core': ['environment'] },
+      plugins: [],
+      ua: [{ segment: 'autocomplete-core', version }],
+    });
+  });
+
+  test('exposes user agents', async () => {
+    createPlayground(createAutocomplete, {
+      environment: algoliaCrawlerEnvironment,
+    });
+
+    await defer(noop, 0);
+
+    expect(
+      JSON.parse(
+        document.head.querySelector<HTMLMetaElement>(
+          'meta[name="algolia:metadata"]'
+        ).content
+      ).ua
+    ).toEqual([{ segment: 'autocomplete-core', version }]);
+  });
+
+  test('exposes passed options', async () => {
+    createPlayground(createAutocomplete, {
+      openOnFocus: true,
+      placeholder: 'Start searching',
+      environment: algoliaCrawlerEnvironment,
+    });
+
+    await defer(noop, 0);
+
+    expect(
+      JSON.parse(
+        document.head.querySelector<HTMLMetaElement>(
+          'meta[name="algolia:metadata"]'
+        ).content
+      ).options
+    ).toEqual({
+      'autocomplete-core': ['openOnFocus', 'placeholder', 'environment'],
+    });
+  });
+
+  test('exposes passed plugins and their passed options', async () => {
+    const algoliaInsightsPlugin = createAlgoliaInsightsPlugin({
+      insightsClient,
+      onItemsChange: noop,
+    });
+
+    createPlayground(createAutocomplete, {
+      environment: algoliaCrawlerEnvironment,
+      plugins: [algoliaInsightsPlugin],
+    });
+
+    await defer(noop, 0);
+
+    expect(
+      JSON.parse(
+        document.head.querySelector<HTMLMetaElement>(
+          'meta[name="algolia:metadata"]'
+        ).content
+      ).plugins
+    ).toEqual([
+      {
+        name: 'aa.algoliaInsightsPlugin',
+        options: ['insightsClient', 'onItemsChange'],
+      },
+    ]);
+  });
+
+  test('exposes custom plugins', async () => {
+    createPlayground(createAutocomplete, {
+      environment: algoliaCrawlerEnvironment,
+      plugins: [
+        {
+          name: 'customPlugin',
+        },
+      ],
+    });
+
+    await defer(noop, 0);
+
+    expect(
+      JSON.parse(
+        document.head.querySelector<HTMLMetaElement>(
+          'meta[name="algolia:metadata"]'
+        ).content
+      ).plugins
+    ).toEqual([{ name: 'customPlugin', options: [] }]);
+  });
+
+  test('does not set a fallback name for unnamed custom plugins', async () => {
+    createPlayground(createAutocomplete, {
+      environment: algoliaCrawlerEnvironment,
+      plugins: [{}],
+    });
+
+    await defer(noop, 0);
+
+    expect(
+      JSON.parse(
+        document.head.querySelector<HTMLMetaElement>(
+          'meta[name="algolia:metadata"]'
+        ).content
+      ).plugins
+    ).toEqual([{ options: [] }]);
+  });
+});
+
+function createEnvironmentWithUserAgent(userAgent: string) {
+  return {
+    ...global,
+    navigator: {
+      ...global.navigator,
+      userAgent,
+    },
+  };
+}
diff --git a/packages/autocomplete-core/src/createAutocomplete.ts b/packages/autocomplete-core/src/createAutocomplete.ts
@@ -3,6 +3,7 @@ import { createStore } from './createStore';
 import { getAutocompleteSetters } from './getAutocompleteSetters';
 import { getDefaultProps } from './getDefaultProps';
 import { getPropGetters } from './getPropGetters';
+import { getMetadata, injectMetadata } from './metadata';
 import { onInput } from './onInput';
 import { stateReducer } from './stateReducer';
 import {
@@ -12,7 +13,7 @@ import {
   AutocompleteSubscribers,
 } from './types';
 
-interface AutocompleteOptions<TItem extends BaseItem>
+export interface AutocompleteOptionsWithMetadata<TItem extends BaseItem>
   extends AutocompleteCoreOptions<TItem> {
   /**
    * @internal
@@ -26,7 +27,7 @@ export function createAutocomplete<
   TMouseEvent = MouseEvent,
   TKeyboardEvent = KeyboardEvent
 >(
-  options: AutocompleteOptions<TItem>
+  options: AutocompleteOptionsWithMetadata<TItem>
 ): AutocompleteApi<TItem, TEvent, TMouseEvent, TKeyboardEvent> {
   checkOptions(options);
 
@@ -71,6 +72,11 @@ export function createAutocomplete<
     })
   );
 
+  injectMetadata({
+    metadata: getMetadata({ plugins: props.plugins, options }),
+    environment: props.environment,
+  });
+
   return {
     refresh,
     ...propGetters,

diff --git a/packages/autocomplete-core/src/metadata.ts b/packages/autocomplete-core/src/metadata.ts
@@ -0,0 +1,80 @@
+import { UserAgent, userAgents } from '@algolia/autocomplete-shared';
+
+import {
+  AutocompleteEnvironment,
+  AutocompleteOptions,
+  AutocompleteOptionsWithMetadata,
+  AutocompletePlugin,
+  BaseItem,
+} from '.';
+
+type AutocompleteMetadata = {
+  plugins: Array<{
+    name: string | undefined;
+    options: string[];
+  }>;
+  options: Record<string, string[]>;
+  ua: UserAgent[];
+};
+
+type GetMetadataParams<TItem extends BaseItem, TData = unknown> = {
+  plugins: Array<AutocompletePlugin<TItem, TData>>;
+  options: AutocompleteOptionsWithMetadata<TItem>;
+};
+
+export function getMetadata<TItem extends BaseItem, TData = unknown>({
+  plugins,
+  options,
+}: GetMetadataParams<TItem, TData>) {
+  const optionsKey = ((options.__autocomplete_metadata
+    ?.userAgents as UserAgent[]) || [])[0]?.segment;
+
+  const extraOptions = optionsKey
+    ? {
+        [optionsKey]: Object.keys(
+          (options.__autocomplete_metadata
+            ?.options as AutocompleteOptions<TItem>) || {}
+        ),
+      }
+    : {};
+
+  return {
+    plugins: plugins.map((plugin) => ({
+      name: plugin.name,
+      options: Object.keys(plugin.__autocomplete_pluginOptions || []),
+    })),
+    options: {
+      'autocomplete-core': Object.keys(options),
+      ...extraOptions,
+    },
+    ua: userAgents.concat(
+      (options.__autocomplete_metadata?.userAgents as any) || []
+    ),
+  };
+}
+
+type InlineMetadataParams = {
+  metadata: AutocompleteMetadata;
+  environment: AutocompleteEnvironment;
+};
+
+export function injectMetadata({
+  metadata,
+  environment,
+}: InlineMetadataParams) {
+  const isMetadataEnabled = environment.navigator?.userAgent.includes(
+    'Algolia Crawler'
+  );
+
+  if (isMetadataEnabled) {
+    const metadataContainer = environment.document.createElement('meta');
+    const headRef = environment.document.querySelector('head');
+
+    metadataContainer.name = 'algolia:metadata';
+
+    setTimeout(() => {
+      metadataContainer.content = JSON.stringify(metadata);
+      headRef!.appendChild(metadataContainer);
+    }, 0);
+  }
+}
diff --git a/packages/autocomplete-core/src/types/AutocompleteEnvironment.ts b/packages/autocomplete-core/src/types/AutocompleteEnvironment.ts
@@ -11,4 +11,5 @@ export type AutocompleteEnvironment =
         assign: Location['assign'];
       };
       open: Window['open'];
+      navigator: Window['navigator'];
     };