diff --git a/app/javascript/actions/changePostBoard.ts b/app/javascript/actions/changePostBoard.ts
index e8b94e48..451e9fe6 100644
--- a/app/javascript/actions/changePostBoard.ts
+++ b/app/javascript/actions/changePostBoard.ts
@@ -5,7 +5,7 @@ import { State } from '../reducers/rootReducer';
 export const CHANGE_POST_BOARD_SUCCESS = 'CHANGE_POST_BOARD_SUCCESS';
 export interface ChangePostBoardSuccessAction {
   type: typeof CHANGE_POST_BOARD_SUCCESS;
-  newBoardId;
+  newBoardId: number;
 }
 
 const changePostBoardSuccess = (newBoardId: number): ChangePostBoardSuccessAction => ({
diff --git a/app/javascript/actions/changePostStatus.ts b/app/javascript/actions/changePostStatus.ts
index 29c915d9..c089b32d 100644
--- a/app/javascript/actions/changePostStatus.ts
+++ b/app/javascript/actions/changePostStatus.ts
@@ -5,7 +5,7 @@ import { State } from '../reducers/rootReducer';
 export const CHANGE_POST_STATUS_SUCCESS = 'CHANGE_POST_STATUS_SUCCESS';
 export interface ChangePostStatusSuccessAction {
   type: typeof CHANGE_POST_STATUS_SUCCESS;
-  newPostStatusId;
+  newPostStatusId: number;
 }
 
 const changePostStatusSuccess = (newPostStatusId: number): ChangePostStatusSuccessAction => ({
diff --git a/app/javascript/actions/handleCommentReplies.ts b/app/javascript/actions/handleCommentReplies.ts
index 46b0cedf..db771197 100644
--- a/app/javascript/actions/handleCommentReplies.ts
+++ b/app/javascript/actions/handleCommentReplies.ts
@@ -11,12 +11,12 @@ interface SetCommentReplyBodyAction {
   body: string;
 }
 
-export const toggleCommentReply = (commentId): ToggleCommentReplyAction => ({
+export const toggleCommentReply = (commentId: number): ToggleCommentReplyAction => ({
   type: TOGGLE_COMMENT_REPLY,
   commentId,
 });
 
-export const setCommentReplyBody = (commentId, body): SetCommentReplyBodyAction => ({
+export const setCommentReplyBody = (commentId: number, body: string): SetCommentReplyBodyAction => ({
   type: SET_COMMENT_REPLY_BODY,
   commentId,
   body,
diff --git a/app/javascript/actions/requestComment.ts b/app/javascript/actions/requestComment.ts
index 9f3f67c6..6ce0efc3 100644
--- a/app/javascript/actions/requestComment.ts
+++ b/app/javascript/actions/requestComment.ts
@@ -1,7 +1,7 @@
 import ICommentJSON from '../interfaces/json/IComment';
 
 export const COMMENT_REQUEST_SUCCESS = 'COMMENT_REQUEST_SUCCESS';
-interface CommentRequestSuccessAction {
+export interface CommentRequestSuccessAction {
   type: typeof COMMENT_REQUEST_SUCCESS;
   comment: ICommentJSON;
 }
diff --git a/app/javascript/actions/submitComment.ts b/app/javascript/actions/submitComment.ts
index b7cd5c82..7018ea8d 100644
--- a/app/javascript/actions/submitComment.ts
+++ b/app/javascript/actions/submitComment.ts
@@ -28,7 +28,7 @@ export type CommentSubmitActionTypes =
   CommentSubmitSuccessAction |
   CommentSubmitFailureAction;
 
-const commentSubmitStart = (parentId): CommentSubmitStartAction => ({
+const commentSubmitStart = (parentId: number): CommentSubmitStartAction => ({
   type: COMMENT_SUBMIT_START,
   parentId,
 });
@@ -40,17 +40,17 @@ const commentSubmitSuccess = (
   comment: commentJSON,
 });
 
-const commentSubmitFailure = (parentId, error): CommentSubmitFailureAction => ({
+const commentSubmitFailure = (parentId: number, error: string): CommentSubmitFailureAction => ({
   type: COMMENT_SUBMIT_FAILURE,
   parentId,
   error,
 });
 
 export const submitComment = (
-  postId,
-  body,
-  parentId,
-  authenticityToken,
+  postId: number,
+  body: string,
+  parentId: number,
+  authenticityToken: string,
 ): ThunkAction<void, State, null, Action<string>> => async (dispatch) => {
   dispatch(commentSubmitStart(parentId));
 
diff --git a/app/javascript/components/Board/index.tsx b/app/javascript/components/Board/index.tsx
index ac8194bf..6fceedba 100644
--- a/app/javascript/components/Board/index.tsx
+++ b/app/javascript/components/Board/index.tsx
@@ -6,6 +6,9 @@ import createStoreHelper from '../../helpers/createStore';
 
 import IBoard from '../../interfaces/IBoard';
 
+import { Store } from 'redux';
+import { State } from '../../reducers/rootReducer';
+
 interface Props {
   board: IBoard;
   isLoggedIn: boolean;
@@ -13,7 +16,7 @@ interface Props {
 }
 
 class BoardRoot extends React.Component<Props> {
-  store: any;
+  store: Store<State, any>;
 
   constructor(props: Props) {
     super(props);
diff --git a/app/javascript/components/Post/index.tsx b/app/javascript/components/Post/index.tsx
index 3c00c38d..397d6b73 100644
--- a/app/javascript/components/Post/index.tsx
+++ b/app/javascript/components/Post/index.tsx
@@ -8,6 +8,9 @@ import Post from '../../containers/Post';
 import IBoard from '../../interfaces/IBoard';
 import IPostStatus from '../../interfaces/IPostStatus';
 
+import { Store } from 'redux';
+import { State } from '../../reducers/rootReducer';
+
 interface Props {
   postId: number;
   boards: Array<IBoard>;
@@ -18,7 +21,7 @@ interface Props {
 }
 
 class PostRoot extends React.Component<Props> {
-  store: any;
+  store: Store<State, any>;
 
   constructor(props: Props) {
     super(props);
diff --git a/app/javascript/containers/Board.tsx b/app/javascript/containers/Board.tsx
index 1f640441..e9e71b25 100644
--- a/app/javascript/containers/Board.tsx
+++ b/app/javascript/containers/Board.tsx
@@ -16,7 +16,7 @@ const mapStateToProps = (state: State) => ({
   postStatuses: state.postStatuses,
 });
 
-const mapDispatchToProps = (dispatch) => ({
+const mapDispatchToProps = (dispatch: any) => ({
   requestPosts(boardId: number, page: number = 1, searchQuery: string = '', postStatusId: number = null) {
     dispatch(requestPosts(boardId, page, searchQuery, postStatusId));
   },
diff --git a/app/javascript/reducers/commentReducer.ts b/app/javascript/reducers/commentReducer.ts
index 9a6d1915..77f1193b 100644
--- a/app/javascript/reducers/commentReducer.ts
+++ b/app/javascript/reducers/commentReducer.ts
@@ -1,4 +1,5 @@
 import {
+  CommentRequestSuccessAction,
   COMMENT_REQUEST_SUCCESS,
 } from '../actions/requestComment';
 
@@ -14,7 +15,7 @@ const initialState: IComment = {
 
 const commentReducer = (
   state = initialState,
-  action,
+  action: CommentRequestSuccessAction,
 ): IComment => {
   switch (action.type) {
     case COMMENT_REQUEST_SUCCESS:
diff --git a/app/javascript/reducers/commentRepliesReducer.ts b/app/javascript/reducers/commentRepliesReducer.ts
index e11e8108..b4924267 100644
--- a/app/javascript/reducers/commentRepliesReducer.ts
+++ b/app/javascript/reducers/commentRepliesReducer.ts
@@ -1,13 +1,16 @@
 import {
+  CommentRequestSuccessAction,
   COMMENT_REQUEST_SUCCESS,
 } from '../actions/requestComment';
 
 import {
+  HandleCommentRepliesType,
   TOGGLE_COMMENT_REPLY,
   SET_COMMENT_REPLY_BODY,
 } from '../actions/handleCommentReplies';
 
 import {
+  CommentSubmitActionTypes,
   COMMENT_SUBMIT_START,
   COMMENT_SUBMIT_SUCCESS,
   COMMENT_SUBMIT_FAILURE,
@@ -31,7 +34,10 @@ const initialState: CommentRepliesState = {
 
 const commentRepliesReducer = (
   state = initialState,
-  action,
+  action:
+    CommentRequestSuccessAction |
+    HandleCommentRepliesType |
+    CommentSubmitActionTypes,
 ) => {
   switch (action.type) {
     case COMMENT_REQUEST_SUCCESS:
diff --git a/app/javascript/reducers/commentsReducer.ts b/app/javascript/reducers/commentsReducer.ts
index 1df52aa0..17e328be 100644
--- a/app/javascript/reducers/commentsReducer.ts
+++ b/app/javascript/reducers/commentsReducer.ts
@@ -1,4 +1,5 @@
 import {
+  CommentsRequestActionTypes,
   COMMENTS_REQUEST_START,
   COMMENTS_REQUEST_SUCCESS,
   COMMENTS_REQUEST_FAILURE,
@@ -7,11 +8,13 @@ import {
 import { commentRequestSuccess } from '../actions/requestComment';
 
 import {
+  HandleCommentRepliesType,
   TOGGLE_COMMENT_REPLY,
   SET_COMMENT_REPLY_BODY,
 } from '../actions/handleCommentReplies';
 
 import {
+  CommentSubmitActionTypes,
   COMMENT_SUBMIT_START,
   COMMENT_SUBMIT_SUCCESS,
   COMMENT_SUBMIT_FAILURE,
@@ -40,7 +43,10 @@ const initialState: CommentsState = {
 
 const commentsReducer = (
   state = initialState,
-  action,
+  action:
+    CommentsRequestActionTypes |
+    HandleCommentRepliesType |
+    CommentSubmitActionTypes
 ): CommentsState => {
   switch (action.type) {
     case COMMENTS_REQUEST_START:
@@ -55,7 +61,7 @@ const commentsReducer = (
         items: action.comments.map(
           (comment: ICommentJSON) => commentReducer(undefined, commentRequestSuccess(comment))
         ),
-        replies: [commentRepliesReducer(undefined, {type: 'COMMENT_REQUEST_SUCCESS', comment: { id: -1 } }),
+        replies: [commentRepliesReducer(undefined, {type: 'COMMENT_REQUEST_SUCCESS', comment: { id: -1 } as ICommentJSON }),
           ...action.comments.map(
             (comment: ICommentJSON) => commentRepliesReducer(undefined, commentRequestSuccess(comment))
         )],
diff --git a/app/javascript/reducers/currentPostReducer.ts b/app/javascript/reducers/currentPostReducer.ts
index 18042bec..ea0a42c6 100644
--- a/app/javascript/reducers/currentPostReducer.ts
+++ b/app/javascript/reducers/currentPostReducer.ts
@@ -50,10 +50,10 @@ interface CurrentPostState {
 }
 
 const initialState: CurrentPostState = {
-  item: postReducer(undefined, {}),
+  item: postReducer(undefined, {} as PostRequestActionTypes),
   isLoading: false,
   error: '',
-  comments: commentsReducer(undefined, {}),
+  comments: commentsReducer(undefined, {} as CommentsRequestActionTypes),
 };
 
 const currentPostReducer = (
diff --git a/app/javascript/reducers/postReducer.ts b/app/javascript/reducers/postReducer.ts
index 6520f70c..1b4dd6b4 100644
--- a/app/javascript/reducers/postReducer.ts
+++ b/app/javascript/reducers/postReducer.ts
@@ -1,12 +1,15 @@
 import {
+  PostRequestActionTypes,
   POST_REQUEST_SUCCESS,
 } from '../actions/requestPost';
 
 import {
+  ChangePostBoardSuccessAction,
   CHANGE_POST_BOARD_SUCCESS,
 } from '../actions/changePostBoard';
 
 import {
+  ChangePostStatusSuccessAction,
   CHANGE_POST_STATUS_SUCCESS,
 } from '../actions/changePostStatus';
 
@@ -25,7 +28,10 @@ const initialState: IPost = {
 
 const postReducer = (
   state = initialState,
-  action,
+  action:
+    PostRequestActionTypes |
+    ChangePostBoardSuccessAction |
+    ChangePostStatusSuccessAction,
 ): IPost => {
   switch (action.type) {
     case POST_REQUEST_SUCCESS:
diff --git a/app/javascript/reducers/postsReducer.ts b/app/javascript/reducers/postsReducer.ts
index c263584c..b9a8b8af 100644
--- a/app/javascript/reducers/postsReducer.ts
+++ b/app/javascript/reducers/postsReducer.ts
@@ -37,10 +37,7 @@ const initialState: PostsState = {
   haveMore: true,
   areLoading: false,
   error: '',
-  filters: { // improve
-    searchQuery: '',
-    postStatusId: null,
-  },
+  filters: filtersReducer(undefined, {} as ChangeFiltersActionTypes),
 };
 
 const postsReducer = (
diff --git a/package.json b/package.json
index 5b3d2976..35b6e956 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
   },
   "version": "0.1.0",
   "devDependencies": {
+    "@types/react-redux": "^7.1.3",
     "redux-devtools-extension": "^2.13.8",
     "webpack-dev-server": "^3.8.0"
   }
diff --git a/yarn.lock b/yarn.lock
index 70df2f20..814223be 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -820,6 +820,14 @@
     "@types/minimatch" "*"
     "@types/node" "*"
 
+"@types/hoist-non-react-statics@^3.3.0":
+  version "3.3.1"
+  resolved "https://registry.yarnpkg.com/@types/hoist-non-react-statics/-/hoist-non-react-statics-3.3.1.tgz#1124aafe5118cb591977aeb1ceaaed1070eb039f"
+  integrity sha512-iMIqiko6ooLrTh1joXodJK5X9xeEALT1kM5G3ZLhD3hszxBdIEd5C75U834D9mLcINgD4OyZf5uQXjkuYydWvA==
+  dependencies:
+    "@types/react" "*"
+    hoist-non-react-statics "^3.3.0"
+
 "@types/minimatch@*":
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/@types/minimatch/-/minimatch-3.0.3.tgz#3dca0e3f33b200fc7d1139c0cd96c1268cadfd9d"
@@ -847,6 +855,16 @@
   dependencies:
     "@types/react" "*"
 
+"@types/react-redux@^7.1.3":
+  version "7.1.3"
+  resolved "https://registry.yarnpkg.com/@types/react-redux/-/react-redux-7.1.3.tgz#7efc1e36267e9bf8b24ec89ac30a27a65c94cd25"
+  integrity sha512-coaQFfn6XrHF/4CSF8eBM9rUbi5TX6qVhS+KF89Z2nC9YdTKTckOpJLJyQocYLrXF0IFX+/ZUJwMvbZ0nNmkDg==
+  dependencies:
+    "@types/hoist-non-react-statics" "^3.3.0"
+    "@types/react" "*"
+    hoist-non-react-statics "^3.3.0"
+    redux "^4.0.0"
+
 "@types/react@*", "@types/react@^16.9.2":
   version "16.9.2"
   resolved "https://registry.yarnpkg.com/@types/react/-/react-16.9.2.tgz#6d1765431a1ad1877979013906731aae373de268"
@@ -5932,7 +5950,7 @@ redux-thunk@^2.3.0:
   resolved "https://registry.yarnpkg.com/redux-thunk/-/redux-thunk-2.3.0.tgz#51c2c19a185ed5187aaa9a2d08b666d0d6467622"
   integrity sha512-km6dclyFnmcvxhAcrQV2AkZmPQjzPDjgVlQtR0EQjxZPyJ0BnMf3in1ryuR8A2qU0HldVRfxYXbFSKlI3N7Slw==
 
-redux@^4.0.4:
+redux@^4.0.0, redux@^4.0.4:
   version "4.0.4"
   resolved "https://registry.yarnpkg.com/redux/-/redux-4.0.4.tgz#4ee1aeb164b63d6a1bcc57ae4aa0b6e6fa7a3796"
   integrity sha512-vKv4WdiJxOWKxK0yRoaK3Y4pxxB0ilzVx6dszU2W8wLxlb2yikRph4iV/ymtdJ6ZxpBLFbyrxklnT5yBbQSl3Q==