v4.0.0

* **configure:** merge with the previous parameters ([#4085](#4085)) ([a215d0c](a215d0c))
* **configure:** update lifecycle state ([#3994](#3994)) ([3d8d967](3d8d967))
* **connectInfiniteHits:** fix page state when adding or removing widgets ([#4104](#4104)) ([1077340](1077340))
* **connectInfiniteHits:** fix state when navigating or adding/removing widgets ([#4123](#4123)) ([9cbd24a](9cbd24a))
* **createURL:** support multi-index ([#4082](#4082)) ([179a6e5](179a6e5))
* **defer:** recover from error ([#3933](#3933)) ([f22b9e2](f22b9e2))
* **helper:** expose .lastResults to .helper ([#4170](#4170)) ([236eb7b](236eb7b))
* **history:** avoid empty query string ([#4130](#4130)) ([18fee7c](18fee7c))
* **hits:** update lifecycle state ([#3977](#3977)) ([6e55ba6](6e55ba6))
* **hitsPerPage:** avoid sync default value ([#4086](#4086)) ([3f8b958](3f8b958))
* **hitsPerPage:** update lifecycle state ([#3978](#3978)) ([d21d620](d21d620))
* **index:** ensure that we always use the index set by widgets ([#4125](#4125)) ([952dc70](952dc70)), closes [/github.com/algolia/algoliasearch-helper-js/blob/5a0352aa233c5ea932df6b054a16989c8d302404/src/algoliasearch.helper.js#L124](https://github.com//github.com/algolia/algoliasearch-helper-js/blob/5a0352aa233c5ea932df6b054a16989c8d302404/src/algoliasearch.helper.js/issues/L124)
* **index:** prevent render without results ([#3932](#3932)) ([1b9b5f4](1b9b5f4))
* **index:** subscribe to state change only after init for uiState ([#4003](#4003)) ([9490ca9](9490ca9))
* **index:** support custom UI params in UI state warning ([#4165](#4165)) ([80d32fc](80d32fc))
* **index:** warn for inconsistent UI state in development mode ([#4140](#4140)) ([7e277dc](7e277dc))
* **infiniteHits:** update lifecycle state ([#3983](#3983)) ([4b8bee5](4b8bee5))
* **instantsearch:** return instance in widgets methods ([#4143](#4143)) ([77ffb93](77ffb93))
* **InstantSearch:** cancel scheduled operations ([#3930](#3930)) ([3aafbad](3aafbad))
* **InstantSearch:** fix initialUIState when refinements are already present in the route ([#4103](#4103)) ([079db57](079db57))
* **InstantSearch:** remove useless walk/duplicate request ([#4127](#4127)) ([70163a8](70163a8))
* **menu:** apply & remove refinement ([#4027](#4027)) ([85de2cf](85de2cf))
* **menu:** prevent error on stale search ([#3934](#3934)) ([5f9e138](5f9e138))
* **numericMenu:** take array into account for empty state ([#4084](#4084)) ([2c05a01](2c05a01))
* **pagination:** update lifecycle state ([#3979](#3979)) ([2b08344](2b08344))
* **pagination:** update no refinement behavior ([#4124](#4124)) ([8d222ad](8d222ad))
* **range:** clear widget state on empty refinements ([#4157](#4157)) ([23cd112](23cd112))
* **ratingMenu:** update lifecycle state ([#3987](#3987)) ([ffadf64](ffadf64))
* **RefinementList:** remove root css class on sublists ([#4117](#4117)) ([ceddd42](ceddd42)), closes [/github.com/algolia/instantsearch.js/blob/v2/src/decorators/headerFooter.js#L22](https://github.com//github.com/algolia/instantsearch.js/blob/v2/src/decorators/headerFooter.js/issues/L22)
* **searchBox:** update lifecycle state ([#3981](#3981)) ([0ea4950](0ea4950))
* **sortBy:** ensure a return value for getWidgetSearchParameters ([#4126](#4126)) ([569d573](569d573))
* **sortBy:** read initial index name from parent index ([#4079](#4079)) ([fe23c55](fe23c55))
* display warnings only in development ([#4150](#4150)) ([44f69a0](44f69a0))
* remove useless types  ([#3958](#3958)) ([ddebf53](ddebf53))
* **stories:** hide Places ([#4152](#4152)) ([7ff843f](7ff843f))
* **toggleRefinement:** update lifecycle state ([#3993](#3993)) ([f1beff6](f1beff6))
* **voiceSearch:** update lifecycle state ([#3982](#3982)) ([798e3c1](798e3c1))
* **warnings:** remove v3 warnings ([#4134](#4134)) ([7eb6810](7eb6810))

* **autocomplete:** leverage scoped results ([#3975](#3975)) ([8f05968](8f05968))
* **autocomplete:** participate in routing ([#4029](#4029)) ([a9ca0c5](a9ca0c5))
* **autocomplete:** provide indexId ([#4142](#4142)) ([b641e23](b641e23))
* **clearRefinements:** support multiple indices ([#4036](#4036)) ([3611b11](3611b11))
* **connectAutocomplete:** add default value on getConfiguration ([#3836](#3836)) ([724b83f](724b83f))
* **connectAutocomplete:** clear the state on dispose ([#3815](#3815)) ([8ae87d8](8ae87d8))
* **connectHierarchicalMenu:** update getWidgetSearchParameters ([#4053](#4053)) ([c99f822](c99f822))
* **connectHits:** clear the state on dispose ([#3816](#3816)) ([c4de730](c4de730))
* **connectHits:** implement getWidgetSearchParameters ([#4001](#4001)) ([c77cf66](c77cf66))
* **connectHitsPerPage:** clear the state on dispose ([#3818](#3818)) ([d7a5c89](d7a5c89))
* **connectInfiniteHits:** add default value on getConfiguration ([#3837](#3837)) ([8c65249](8c65249))
* **connectInfiniteHits:** clear the state on dispose ([#3819](#3819)) ([60ce151](60ce151))
* **connectMenu:** update getWidgetSearchParameters ([#4054](#4054)) ([7d001e7](7d001e7))
* **connectNumericMenu:** update state lifecycle  ([#4013](#4013)) ([2620c90](2620c90))
* **connectPagination:** add default value on getConfiguration ([#3838](#3838)) ([aa4602c](aa4602c))
* **connectPagination:** clear the state on dispose ([#3821](#3821)) ([5b8ef49](5b8ef49))
* **connectPagination:** update getWidgetSearchParameters ([#4004](#4004)) ([eed7e77](eed7e77))
* **connectRange:** default `precision` to 0 ([#3953](#3953)) ([632e06b](632e06b))
* **connectRatingMenu:** update getWidgetSearchParameters  ([#4008](#4008)) ([d3c96bf](d3c96bf))
* **connectRefinementList:** update getWidgetSearchParameters  ([#4010](#4010)) ([ddc8fc4](ddc8fc4))
* **connectSearchBox:** clear the state on dispose ([#3822](#3822)) ([940522c](940522c))
* **connectSearchBox:** mount with a default query ([#3840](#3840)) ([c3a7d69](c3a7d69))
* **connectSearchBox:** update getWidgetSearchParameters ([#4002](#4002)) ([5c6fcd8](5c6fcd8))
* **connectVoiceSearch:** add default value on getConfiguration ([#3841](#3841)) ([fb70363](fb70363))
* **connectVoiceSearch:** clear the state on dispose ([#3823](#3823)) ([705b3e6](705b3e6))
* **connectVoiceSearch:** update getWidgetSearchParameters ([#4055](#4055)) ([b8c669f](b8c669f))
* **core:** deprecate addWidget & removeWidget ([#4131](#4131)) ([e5dafef](e5dafef))
* **currentRefinements:** support multiple indices ([#4012](#4012)) ([e997728](e997728))
* **defer:** implement cancellable callback ([#3916](#3916)) ([43a0bf8](43a0bf8))
* **federated:** keep a consistent state in the RefinementList life cycle ([#3976](#3976)) ([31d0fd6](31d0fd6))
* **hitsPerPage:** support new routing system ([#4038](#4038)) ([02502cb](02502cb)), closes [#4069](#4069)
* **index:** accept indexId ([#4070](#4070)) ([b74f8e3](b74f8e3))
* **index:** add mergeSearchParameters function ([#3917](#3917)) ([c0fe7bb](c0fe7bb))
* **index:** add widget ([dbbda0f](dbbda0f)), closes [#3892](#3892) [#3893](#3893) [#3914](#3914)
* **index:** compute local uiState ([#3997](#3997)) ([997c0f4](997c0f4))
* **index:** merge `ruleContexts` search parameter ([#3944](#3944)) ([e94752d](e94752d))
* **index:** provide scoped results to render hook ([#3964](#3964)) ([37c6aad](37c6aad))
* **index:** replicate searchFunction hack ([#4078](#4078)) ([1d2a816](1d2a816)), closes [/github.com/algolia/instantsearch.js/blob/509513c0feafaad522f6f18d87a441559f4aa050/src/lib/RoutingManager.ts#L113-L130](https://github.com//github.com/algolia/instantsearch.js/blob/509513c0feafaad522f6f18d87a441559f4aa050/src/lib/RoutingManager.ts/issues/L113-L130)
* **index:** reset page of child indexes ([#3962](#3962)) ([131b1ce](131b1ce))
* **index:** resolve parent SearchParameters ([#3937](#3937)) ([2611da5](2611da5))
* **index:** use uiState driven SearchParameters ([#4059](#4059)) ([b12bb9f](b12bb9f))
* **infiniteHits:** support new routing system ([#4040](#4040)) ([49315cf](49315cf))
* **instantsearch:** add onStateChange method ([#4080](#4080)) ([9f68da5](9f68da5))
* **InstantSearch:** switch to DerivedHelper only ([#3885](#3885)) ([d6fc317](d6fc317))
* **places:** add Places widget ([#4167](#4167)) ([1d754d1](1d754d1))
* drop support of searchParameters for initialUiState ([#4081](#4081)) ([571efeb](571efeb))
* **range:** support new routing system ([#4039](#4039)) ([8cba05a](8cba05a))
* **routing:** add a "single index" compatibility mode ([#4087](#4087)) ([842eb0f](842eb0f))
* **RoutingManager:** update state on route update ([#4100](#4100)) ([88f2615](88f2615))
* **toggleRefinement:** support new routing system ([#4037](#4037)) ([6a9d99f](6a9d99f))
* **types:** DerivedHelper ([#3887](#3887)) ([0f38b4a](0f38b4a))
* **types:** rename RenderOptions -> RendererOptions ([#3867](#3867)) ([05c6f72](05c6f72))
* **utils:** implement defer ([#3882](#3882)) ([8af470e](8af470e))
* **voice:** add additional query parameters ([#3738](#3738)) ([c555255](c555255))
* drop suppot for onHistoryChange ([#3941](#3941)) ([697f609](697f609))
* introduce initialUiState option ([#4074](#4074)) ([de00707](de00707))
* update UiState definition ([#4075](#4075)) ([9e7d3d8](9e7d3d8))
* **widgets:** add `$$type` to widgets definition ([#3960](#3960)) ([344d1b7](344d1b7))