diff --git a/app/actions/usersTyping.js b/app/actions/usersTyping.js
deleted file mode 100644
index fb8f5980..00000000
--- a/app/actions/usersTyping.js
+++ /dev/null
@@ -1,21 +0,0 @@
-import { USERS_TYPING } from './actionsTypes';
-
-export function addUserTyping(username) {
-	return {
-		type: USERS_TYPING.ADD,
-		username
-	};
-}
-
-export function removeUserTyping(username) {
-	return {
-		type: USERS_TYPING.REMOVE,
-		username
-	};
-}
-
-export function clearUserTyping() {
-	return {
-		type: USERS_TYPING.CLEAR
-	};
-}
diff --git a/app/actions/usersTyping.ts b/app/actions/usersTyping.ts
new file mode 100644
index 00000000..19077ce6
--- /dev/null
+++ b/app/actions/usersTyping.ts
@@ -0,0 +1,29 @@
+import { Action } from 'redux';
+
+import { USERS_TYPING } from './actionsTypes';
+
+export interface IUsersTypingGenericAction extends Action {
+	username: string;
+}
+
+export type TActionUserTyping = IUsersTypingGenericAction & Action;
+
+export function addUserTyping(username: string): IUsersTypingGenericAction {
+	return {
+		type: USERS_TYPING.ADD,
+		username
+	};
+}
+
+export function removeUserTyping(username: string): IUsersTypingGenericAction {
+	return {
+		type: USERS_TYPING.REMOVE,
+		username
+	};
+}
+
+export function clearUserTyping(): Action {
+	return {
+		type: USERS_TYPING.CLEAR
+	};
+}
diff --git a/app/definitions/redux/index.ts b/app/definitions/redux/index.ts
index e95763e2..88b7169e 100644
--- a/app/definitions/redux/index.ts
+++ b/app/definitions/redux/index.ts
@@ -3,6 +3,7 @@ import { TActionActiveUsers } from '../../actions/activeUsers';
 // REDUCERS
 import { IActiveUsers } from '../../reducers/activeUsers';
 import { ISelectedUsers } from '../../reducers/selectedUsers';
+import { TActionUserTyping } from '../../actions/usersTyping';
 
 export interface IApplicationState {
 	settings: any;
@@ -28,4 +29,4 @@ export interface IApplicationState {
 	roles: any;
 }
 
-export type TApplicationActions = TActionActiveUsers & TActionSelectedUsers;
+export type TApplicationActions = TActionActiveUsers & TActionSelectedUsers & TActionUserTyping;
diff --git a/app/reducers/usersTyping.test.ts b/app/reducers/usersTyping.test.ts
new file mode 100644
index 00000000..26e52788
--- /dev/null
+++ b/app/reducers/usersTyping.test.ts
@@ -0,0 +1,30 @@
+import { addUserTyping, removeUserTyping, clearUserTyping } from '../actions/usersTyping';
+import { mockedStore } from './mockedStore';
+import { initialState } from './usersTyping';
+
+describe('test usersTyping reducer', () => {
+	it('should return initial state', () => {
+		const state = mockedStore.getState().usersTyping;
+		expect(state).toEqual(initialState);
+	});
+
+	it('should return modified store after addUserTyping', () => {
+		mockedStore.dispatch(addUserTyping('diego'));
+		mockedStore.dispatch(addUserTyping('carlos'));
+		mockedStore.dispatch(addUserTyping('maria'));
+		const state = mockedStore.getState().usersTyping;
+		expect(state).toEqual(['diego', 'carlos', 'maria']);
+	});
+
+	it('should return modified store after removeUserTyping', () => {
+		mockedStore.dispatch(removeUserTyping('diego'));
+		const state = mockedStore.getState().usersTyping;
+		expect(state).toEqual(['carlos', 'maria']);
+	});
+
+	it('should return initial state after reset', () => {
+		mockedStore.dispatch(clearUserTyping());
+		const state = mockedStore.getState().usersTyping;
+		expect(state).toEqual(initialState);
+	});
+});
diff --git a/app/reducers/usersTyping.js b/app/reducers/usersTyping.ts
similarity index 72%
rename from app/reducers/usersTyping.js
rename to app/reducers/usersTyping.ts
index acecab63..ecfbbb77 100644
--- a/app/reducers/usersTyping.js
+++ b/app/reducers/usersTyping.ts
@@ -1,8 +1,11 @@
 import { USERS_TYPING } from '../actions/actionsTypes';
+import { TApplicationActions } from '../definitions';
 
-const initialState = [];
+export type IUsersTyping = string[];
 
-export default function usersTyping(state = initialState, action) {
+export const initialState: IUsersTyping = [];
+
+export default function usersTyping(state = initialState, action: TApplicationActions): IUsersTyping {
 	switch (action.type) {
 		case USERS_TYPING.ADD:
 			if (state.findIndex(item => item === action.username) === -1) {