feat: identify router

packages/instantsearch.js/src/lib/routers/history.ts

@@ -36,6 +36,7 @@ const setWindowTitle = (title?: string): void => {
 };
 
 class BrowserHistory<TRouteState> implements Router<TRouteState> {
+  public $$type = 'ais.browser';
   /**
    * Transforms a UI state into a title for the page.
    */

packages/instantsearch.js/src/lib/stateMappings/simple.ts

@@ -14,6 +14,8 @@ export default function simpleStateMapping<
   TUiState extends UiState = UiState
 >(): StateMapping<TUiState, TUiState> {
   return {
+    $$type: 'ais.simple',
+
     stateToRoute(uiState) {
       return Object.keys(uiState).reduce(
         (state, indexId) => ({

packages/instantsearch.js/src/lib/stateMappings/singleIndex.ts

@@ -13,6 +13,7 @@ export default function singleIndexStateMapping<
   indexName: keyof TUiState
 ): StateMapping<TUiState, TUiState[typeof indexName]> {
   return {
+    $$type: 'ais.singleIndex',
     stateToRoute(uiState) {
       return getIndexStateWithoutConfigure(uiState[indexName] || {});
     },

packages/instantsearch.js/src/middlewares/createRouterMiddleware.ts

@@ -68,7 +68,9 @@ export const createRouterMiddleware = <
     const initialUiState = instantSearchInstance._initialUiState;
 
     return {
-      $$type: 'ais.router',
+      $$type: `ais.router({router:${
+        router.$$type || '__unknown__'
+      }, stateMapping:${stateMapping.$$type || '__unknown__'}})`,
       $$internal,
       onStateChange({ uiState }) {
         const routeState = stateMapping.stateToRoute(uiState);

packages/instantsearch.js/src/types/router.ts

@@ -35,6 +35,11 @@ export type Router<TRouteState = UiState> = {
    * Called when InstantSearch is disposed. Used to remove subscriptions.
    */
   dispose(): void;
+
+  /**
+   * Identifier for this router. Used to differentiate between routers.
+   */
+  $$type?: string;
 };
 
 /**
@@ -57,4 +62,9 @@ export type StateMapping<TUiState = UiState, TRouteState = TUiState> = {
    * The format is the output of `stateToRoute`.
    */
   routeToState(routeState: TRouteState): TUiState;
+
+  /**
+   * Identifier for this stateMapping. Used to differentiate between stateMappings.
+   */
+  $$type?: string;
 };

packages/react-instantsearch-hooks-router-nextjs/src/index.ts

@@ -165,6 +165,7 @@ export function createInstantSearchRouterNext<TRouteState = UiState>(
     ...routerOptions,
   });
   router._isNextRouter = true;
+  router.$$type = 'ais.nextjs';
 
   return router;
 }