feat(docsearch): introduce transformSearchClient API

`transformSearchClient` allows to attach user agents to the search client, to manipulate the cache, etc.

src/DocSearchModal.tsx

@@ -9,9 +9,10 @@ import { MAX_QUERY_SIZE } from './constants';
 import {
   DocSearchHit,
   InternalDocSearchHit,
+  SearchClient,
   StoredDocSearchHit,
 } from './types';
-import { groupBy, noop } from './utils';
+import { groupBy, identity, noop } from './utils';
 import { createStoredSearches } from './stored-searches';
 import { useSearchClient } from './useSearchClient';
 import { useTrapFocus } from './useTrapFocus';
@@ -23,26 +24,24 @@ import { ScreenState } from './ScreenState';
 import { Footer } from './Footer';
 
 interface DocSearchModalProps extends DocSearchProps {
+  transformSearchClient?(searchClient: SearchClient): SearchClient;
   initialScrollY: number;
   onClose?(): void;
 }
 
-function defaultTransformItems(x: DocSearchHit[]) {
-  return x;
-}
-
 export function DocSearchModal({
   appId = 'BH4D9OD16A',
   apiKey,
   indexName,
   placeholder = 'Search docs',
   searchParameters,
   onClose = noop,
-  transformItems = defaultTransformItems,
+  transformItems = identity,
   hitComponent = Hit,
   resultsFooterComponent = () => null,
   navigator,
   initialScrollY = 0,
+  transformSearchClient = identity,
 }: DocSearchModalProps) {
   const [state, setState] = React.useState<
     AutocompleteState<InternalDocSearchHit>
@@ -62,7 +61,7 @@ export function DocSearchModal({
       : ''
   ).current;
 
-  const searchClient = useSearchClient(appId, apiKey);
+  const searchClient = useSearchClient(appId, apiKey, transformSearchClient);
   const favoriteSearches = React.useRef(
     createStoredSearches<StoredDocSearchHit>({
       key: `__DOCSEARCH_FAVORITE_SEARCHES__${indexName}`,

src/types/SearchClient.ts

@@ -0,0 +1 @@
+export type SearchClient = any;

src/types/index.ts

@@ -1,3 +1,4 @@
 export * from './DocSearchHit';
 export * from './InternalDocSearchHit';
+export * from './SearchClient';
 export * from './StoredDocSearchHit';

src/useSearchClient.ts

@@ -1,15 +1,20 @@
 import React from 'react';
 import algoliasearch from 'algoliasearch/dist/algoliasearch-lite.esm.browser';
 
+import { SearchClient } from './types';
 import { version } from './version';
 
-export function useSearchClient(appId: string, apiKey: string) {
+export function useSearchClient(
+  appId: string,
+  apiKey: string,
+  transformSearchClient: (searchClient: SearchClient) => SearchClient
+): SearchClient {
   const searchClient = React.useMemo(() => {
     const client = algoliasearch(appId, apiKey);
     client.addAlgoliaAgent(`docsearch (${version})`);
 
-    return client;
-  }, [appId, apiKey]);
+    return transformSearchClient(client);
+  }, [appId, apiKey, transformSearchClient]);
 
   return searchClient;
 }

src/utils/identity.ts

@@ -0,0 +1,3 @@
+export function identity<TParam>(x: TParam): TParam {
+  return x;
+}

src/utils/index.ts

@@ -1,2 +1,3 @@
 export * from './groupBy';
+export * from './identity';
 export * from './noop';