diff --git a/react/features/app/types.ts b/react/features/app/types.ts
index b0c363624..da7ca2f59 100644
--- a/react/features/app/types.ts
+++ b/react/features/app/types.ts
@@ -19,6 +19,8 @@ import { IResponsiveUIState } from '../base/responsive-ui/reducer';
 import { ISettingsState } from '../base/settings/reducer';
 import { ISoundsState } from '../base/sounds/reducer';
 import { ITestingState } from '../base/testing/reducer';
+import { INoSrcDataState, ITracksState } from '../base/tracks/reducer';
+import { IUserInteractionState } from '../base/user-interaction/reducer';
 import { INoiseSuppressionState } from '../noise-suppression/reducer';
 
 export interface IStore {
@@ -45,9 +47,12 @@ export interface IState {
     'features/base/logging': ILoggingState,
     'features/base/media': IMediaState,
     'features/base/net-info': INetInfoState,
+    'features/base/no-src-data': INoSrcDataState,
     'features/base/responsive-ui': IResponsiveUIState,
     'features/base/settings': ISettingsState,
     'features/base/sounds': ISoundsState,
+    'features/base/tracks': ITracksState,
+    'features/base/user-interaction': IUserInteractionState,
     'features/noise-suppression': INoiseSuppressionState,
     'features/testing': ITestingState
 }
diff --git a/react/features/base/tracks/reducer.js b/react/features/base/tracks/reducer.ts
similarity index 80%
rename from react/features/base/tracks/reducer.js
rename to react/features/base/tracks/reducer.ts
index ad0af451a..d44b93759 100644
--- a/react/features/base/tracks/reducer.js
+++ b/react/features/base/tracks/reducer.ts
@@ -1,5 +1,6 @@
-import { PARTICIPANT_ID_CHANGED } from '../participants';
-import { ReducerRegistry, set } from '../redux';
+import { PARTICIPANT_ID_CHANGED } from '../participants/actionTypes';
+import ReducerRegistry from '../redux/ReducerRegistry';
+import { set } from '../redux/functions';
 
 import {
     SET_NO_SRC_DATA_NOTIFICATION_UID,
@@ -13,6 +14,19 @@ import {
     TRACK_WILL_CREATE
 } from './actionTypes';
 
+interface ITrack {
+    isReceivingData: boolean;
+    jitsiTrack: Object;
+    lastMediaEvent?: string;
+    local: boolean;
+    mediaType: string;
+    mirror: boolean;
+    muted: boolean;
+    participantId: string;
+    videoStarted: boolean;
+    videoType?: string|null;
+}
+
 /**
  * Track type.
  *
@@ -52,7 +66,7 @@ import {
  * @param {Participant} action.participant - Information about participant.
  * @returns {Track|undefined}
  */
-function track(state, action) {
+function track(state: ITrack, action: any) {
     switch (action.type) {
     case PARTICIPANT_ID_CHANGED:
         if (state.participantId === action.oldValue) {
@@ -70,6 +84,7 @@ function track(state, action) {
             // Make sure that there's an actual update in order to reduce the
             // risk of unnecessary React Component renders.
             for (const p in t) {
+                // @ts-ignore
                 if (state[p] !== t[p]) {
                     // There's an actual update.
                     return {
@@ -115,16 +130,18 @@ function track(state, action) {
     return state;
 }
 
+export type ITracksState = ITrack[];
+
 /**
  * Listen for actions that mutate (e.g. Add, remove) local and remote tracks.
  */
-ReducerRegistry.register('features/base/tracks', (state = [], action) => {
+ReducerRegistry.register('features/base/tracks', (state: ITracksState = [], action) => {
     switch (action.type) {
     case PARTICIPANT_ID_CHANGED:
     case TRACK_NO_DATA_FROM_SOURCE:
     case TRACK_UPDATE_LAST_VIDEO_MEDIA_EVENT:
     case TRACK_UPDATED:
-        return state.map(t => track(t, action));
+        return state.map((t: ITrack) => track(t, action));
 
     case TRACK_ADDED: {
         let withoutTrackStub = state;
@@ -132,7 +149,7 @@ ReducerRegistry.register('features/base/tracks', (state = [], action) => {
         if (action.track.local) {
             withoutTrackStub
                 = state.filter(
-                    t => !t.local || t.mediaType !== action.track.mediaType);
+                    (t: ITrack) => !t.local || t.mediaType !== action.track.mediaType);
         }
 
         return [ ...withoutTrackStub, action.track ];
@@ -140,11 +157,11 @@ ReducerRegistry.register('features/base/tracks', (state = [], action) => {
 
     case TRACK_CREATE_CANCELED:
     case TRACK_CREATE_ERROR: {
-        return state.filter(t => !t.local || t.mediaType !== action.trackType);
+        return state.filter((t: ITrack) => !t.local || t.mediaType !== action.trackType);
     }
 
     case TRACK_REMOVED:
-        return state.filter(t => t.jitsiTrack !== action.track.jitsiTrack);
+        return state.filter((t: ITrack) => t.jitsiTrack !== action.track.jitsiTrack);
 
     case TRACK_WILL_CREATE:
         return [ ...state, action.track ];
@@ -154,10 +171,14 @@ ReducerRegistry.register('features/base/tracks', (state = [], action) => {
     }
 });
 
+export interface INoSrcDataState {
+    noSrcDataNotificationUid?: string|number;
+}
+
 /**
  * Listen for actions that mutate the no-src-data state, like the current notification id.
  */
-ReducerRegistry.register('features/base/no-src-data', (state = {}, action) => {
+ReducerRegistry.register('features/base/no-src-data', (state: INoSrcDataState = {}, action) => {
     switch (action.type) {
     case SET_NO_SRC_DATA_NOTIFICATION_UID:
         return set(state, 'noSrcDataNotificationUid', action.uid);
diff --git a/react/features/base/user-interaction/reducer.js b/react/features/base/user-interaction/reducer.ts
similarity index 64%
rename from react/features/base/user-interaction/reducer.js
rename to react/features/base/user-interaction/reducer.ts
index bb2c8a924..54c8f28f6 100644
--- a/react/features/base/user-interaction/reducer.js
+++ b/react/features/base/user-interaction/reducer.ts
@@ -1,11 +1,14 @@
-// @flow
-
-import { APP_WILL_MOUNT, APP_WILL_UNMOUNT } from '../app';
-import { ReducerRegistry } from '../redux';
+import { APP_WILL_MOUNT, APP_WILL_UNMOUNT } from '../app/actionTypes';
+import ReducerRegistry from '../redux/ReducerRegistry';
 
 import { USER_INTERACTION_RECEIVED } from './actionTypes';
 
-ReducerRegistry.register('features/base/user-interaction', (state = {}, action) => {
+export interface IUserInteractionState {
+    interacted?: boolean;
+}
+
+
+ReducerRegistry.register('features/base/user-interaction', (state: IUserInteractionState = {}, action) => {
     switch (action.type) {
     case APP_WILL_MOUNT:
     case APP_WILL_UNMOUNT: