fix(autocomplete-js): display warning when there are more than one instances of autocomplete

packages/autocomplete-js/src/__tests__/autocomplete.test.ts

@@ -23,6 +23,24 @@ beforeEach(() => {
 });
 
 describe('autocomplete-js', () => {
+  test('warns when more than one instance is detected in a document', () => {
+    const firstContainer = document.createElement('div');
+    expect(() =>
+      autocomplete({
+        container: firstContainer,
+      })
+    ).not.toWarnDev();
+
+    const secondContainer = document.createElement('div');
+    expect(() =>
+      autocomplete({
+        container: secondContainer,
+      })
+    ).toWarnDev(
+      '[Autocomplete] Multiple instances of Autocomplete are not currently supported and can introduce unwanted behavior during user interaction. Please destroy the previous instance before creating a new one.'
+    );
+  });
+
   test('renders with default options', () => {
     const container = document.createElement('div');
     autocomplete<{ label: string }>({

packages/autocomplete-js/src/autocomplete.ts

@@ -7,6 +7,7 @@ import {
   createRef,
   debounce,
   getItemsCount,
+  warn,
 } from '@algolia/autocomplete-shared';
 import htm from 'htm';
 
@@ -27,6 +28,8 @@ import {
 import { userAgents } from './userAgents';
 import { mergeDeep, pickBy, setProperties } from './utils';
 
+let instancesCount = 0;
+
 export function autocomplete<TItem extends BaseItem>(
   options: AutocompleteOptions<TItem>
 ): AutocompleteApi<TItem> {
@@ -336,6 +339,7 @@ export function autocomplete<TItem extends BaseItem>(
   });
 
   function destroy() {
+    instancesCount--;
     cleanupEffects();
   }
 
@@ -397,6 +401,13 @@ export function autocomplete<TItem extends BaseItem>(
     });
   }
 
+  warn(
+    instancesCount === 0,
+    'Multiple instances of Autocomplete are not currently supported and can introduce unwanted behavior during user interaction. Please destroy the previous instance before creating a new one.'
+  );
+
+  instancesCount++;
+
   return {
     ...autocompleteScopeApi,
     update,