feat(hooks): migrate to useSyncExternalStore()

babel.config.js

@@ -50,6 +50,8 @@ module.exports = (api) => {
             'instantsearch.js',
             // React-DOM also fails if the paths are incomplete
             'react-dom',
+            // `use-sync-external-store` also fails if the paths are incomplete
+            'use-sync-external-store',
           ],
         },
       ],

packages/react-instantsearch-hooks-web/rollup.config.js

@@ -26,7 +26,13 @@ const plugins = [
     preferBuiltins: false,
     extensions: ['.mjs', '.js', '.ts', '.jsx', '.tsx', '.json'],
   }),
-  commonjs(),
+  commonjs({
+    namedExports: {
+      '../../node_modules/use-sync-external-store/shim/index.js': [
+        'useSyncExternalStore',
+      ],
+    },
+  }),
   globals(),
   replace({
     'process.env.NODE_ENV': JSON.stringify('production'),

packages/react-instantsearch-hooks/package.json

@@ -48,7 +48,8 @@
   "dependencies": {
     "@babel/runtime": "^7.1.2",
     "algoliasearch-helper": "^3.7.4",
-    "instantsearch.js": "^4.40.1"
+    "instantsearch.js": "^4.40.1",
+    "use-sync-external-store": "^1.0.0"
   },
   "peerDependencies": {
     "algoliasearch": ">= 3.1 < 5",

packages/react-instantsearch-hooks/rollup.config.js

@@ -26,7 +26,13 @@ const plugins = [
     preferBuiltins: false,
     extensions: ['.mjs', '.js', '.ts', '.jsx', '.tsx', '.json'],
   }),
-  commonjs(),
+  commonjs({
+    namedExports: {
+      '../../node_modules/use-sync-external-store/shim/index.js': [
+        'useSyncExternalStore',
+      ],
+    },
+  }),
   globals(),
   replace({
     'process.env.NODE_ENV': JSON.stringify('production'),

packages/react-instantsearch-hooks/src/hooks/useConnector.ts

@@ -83,25 +83,11 @@ export function useConnector<
       }
     );
 
-    const instance = {
+    return {
       ...createWidget(stableProps),
       ...stableAdditionalWidgetProperties,
     };
-
-    // On the server, we add the widget early in the memo to retrieve its search
-    // parameters in the render pass.
-    if (serverContext) {
-      parentIndex.addWidgets([instance]);
-    }
-
-    return instance;
-  }, [
-    connector,
-    parentIndex,
-    serverContext,
-    stableProps,
-    stableAdditionalWidgetProperties,
-  ]);
+  }, [connector, stableProps, stableAdditionalWidgetProperties]);
 
   const [state, setState] = useState<TDescription['renderState']>(() => {
     if (widget.getWidgetRenderState) {
@@ -159,15 +145,19 @@ export function useConnector<
     return {};
   });
 
-  // Using a layout effect adds the widget at the same time as rendering, which
-  // triggers a single network request, instead of two with a regular effect.
   useIsomorphicLayoutEffect(() => {
     parentIndex.addWidgets([widget]);
 
     return () => {
       parentIndex.removeWidgets([widget]);
     };
-  }, [widget, parentIndex]);
+  }, [parentIndex, widget]);
+
+  // On the server, we add the widget early to retrieve its search parameters
+  // in the render pass.
+  if (serverContext && !parentIndex.getWidgets().includes(widget)) {
+    parentIndex.addWidgets([widget]);
+  }
 
   return state;
 }

packages/react-instantsearch-hooks/src/lib/useInstantSearch.ts

@@ -1,5 +1,6 @@
 import InstantSearch from 'instantsearch.js/es/lib/InstantSearch';
-import { useEffect, useMemo, version as ReactVersion } from 'react';
+import { useCallback, useMemo, version as ReactVersion } from 'react';
+import { useSyncExternalStore } from 'use-sync-external-store/shim';
 
 import { useInstantSearchServerContext } from '../lib/useInstantSearchServerContext';
 import { useInstantSearchSSRContext } from '../lib/useInstantSearchSSRContext';
@@ -8,8 +9,6 @@ import version from '../version';
 import { useForceUpdate } from './useForceUpdate';
 import { useStableValue } from './useStableValue';
 
-import type { InstantSearchServerContextApi } from '../components/InstantSearchServerContext';
-import type { InstantSearchServerState } from '../components/InstantSearchSSRProvider';
 import type {
   InstantSearchOptions,
   SearchClient,
@@ -30,84 +29,71 @@ export type UseInstantSearchProps<
 export function useInstantSearch<TUiState extends UiState, TRouteState>(
   props: UseInstantSearchProps<TUiState, TRouteState>
 ) {
+  const forceUpdate = useForceUpdate();
   const serverContext = useInstantSearchServerContext();
   const serverState = useInstantSearchSSRContext();
   const stableProps = useStableValue(props);
-  const search = useMemo(
-    () =>
-      serverAdapter(
-        new InstantSearch(stableProps),
-        stableProps,
-        serverContext,
-        serverState
-      ),
-    [stableProps, serverContext, serverState]
-  );
-  const forceUpdate = useForceUpdate();
+  const search = useMemo(() => {
+    const instance = new InstantSearch(stableProps);
+    const initialResults = serverState?.initialResults;
+
+    if (serverContext || initialResults) {
+      // InstantSearch.js has a private Initial Results API that lets us inject
+      // results on the search instance.
+      // On the server, we default the initial results to an empty object so that
+      // InstantSearch.js doesn't schedule a search that isn't used, leading to
+      // an additional network request. (This is equivalent to monkey-patching
+      // `scheduleSearch` to a noop.)
+      instance._initialResults = initialResults || {};
+    }
 
-  useEffect(() => {
-    addAlgoliaAgents(stableProps.searchClient, defaultUserAgents);
-  }, [stableProps.searchClient]);
+    addAlgoliaAgents(props.searchClient, [
+      ...defaultUserAgents,
+      serverContext && `react-instantsearch-server (${version})`,
+    ]);
 
-  useEffect(() => {
-    // On SSR, the instance is already started so we don't start it again here.
-    if (!search.started) {
+    return instance;
+  }, [
+    props.searchClient,
+    serverContext,
+    serverState?.initialResults,
+    stableProps,
+  ]);
+
+  const store = useSyncExternalStore<InstantSearch<TUiState, TRouteState>>(
+    useCallback(() => {
       search.start();
       forceUpdate();
-    }
 
-    return () => {
-      search.dispose();
-    };
-  }, [search, serverState, forceUpdate]);
-
-  return search;
-}
+      return () => {
+        search.dispose();
+      };
+    }, [forceUpdate, search]),
+    () => search,
+    () => search
+  );
 
-function serverAdapter<TUiState extends UiState, TRouteState>(
-  search: InstantSearch,
-  props: UseInstantSearchProps<TUiState, TRouteState>,
-  serverContext: InstantSearchServerContextApi | null,
-  serverState: Partial<InstantSearchServerState> | null
-): InstantSearch<TUiState, TRouteState> {
-  const initialResults = serverState?.initialResults;
-
-  if (serverContext || initialResults) {
-    // InstantSearch.js has a private Initial Results API that lets us inject
-    // results on the search instance.
-    // On the server, we default the initial results to an empty object so that
-    // InstantSearch.js doesn't schedule a search that isn't used, leading to
-    // an additional network request. (This is equivalent to monkey-patching
-    // `scheduleSearch` to a noop.)
-    search._initialResults = initialResults || {};
+  if (serverContext && !search.started) {
     // On the server, we start the search early to compute the search parameters.
-    // On SSR, we start the search early to directly catch up with the lifecycle
-    // and render.
     search.start();
-  }
-
-  if (serverContext) {
-    // On the browser, we add user agents in an effect. Since effects are not
-    // run on the server, we need to add user agents directly here.
-    addAlgoliaAgents(props.searchClient, [
-      ...defaultUserAgents,
-      `react-instantsearch-server (${version})`,
-    ]);
 
     // We notify `getServerState()` of the InstantSearch internals to retrieve
     // the server state and pass it to the render on SSR.
     serverContext.notifyServer({ search });
   }
 
-  return search;
+  return store;
 }
 
-function addAlgoliaAgents(searchClient: SearchClient, userAgents: string[]) {
+function addAlgoliaAgents(
+  searchClient: SearchClient,
+  userAgents: Array<string | null>
+) {
   if (typeof searchClient.addAlgoliaAgent !== 'function') {
     return;
   }
 
-  userAgents.forEach((userAgent) => {
-    searchClient.addAlgoliaAgent!(userAgent);
+  userAgents.filter(Boolean).forEach((userAgent) => {
+    searchClient.addAlgoliaAgent!(userAgent!);
   });
 }