diff --git a/package.json b/package.json
index 20a3c87..3f7562b 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,11 @@
     "@testing-library/jest-dom": "^5.16.5",
     "@testing-library/react": "^13.4.0",
     "@testing-library/user-event": "^13.5.0",
+    "@types/jest": "^29.2.5",
+    "@types/node": "^18.11.18",
+    "@types/react": "^18.0.26",
+    "@types/react-dom": "^18.0.10",
+    "@types/styled-components": "^5.1.26",
     "dotenv": "^16.0.3",
     "firebase": "^9.14.0",
     "react": "^18.2.0",
@@ -22,6 +27,7 @@
     "sass": "^1.56.1",
     "stripe": "^11.5.0",
     "styled-components": "^5.3.6",
+    "typescript": "^4.9.4",
     "web-vitals": "^2.1.4"
   },
   "scripts": {
diff --git a/src/App.js b/src/App.js
index 4cfbbf5..5e26daf 100644
--- a/src/App.js
+++ b/src/App.js
@@ -14,9 +14,14 @@ const App = ()=> {
   
   useEffect(() => {
     const unsubscribe = onAuthStateChangeListener((user)=>{
+      const createUser = async (user) => {
+        const userSnapshot = await createUserDocumentFromAuth(user);
+        return userSnapshot;
+      };
       if (user) { 
-        const userSnapshot = createUserDocumentFromAuth(user); 
-        dispatch(setUser(user)); // TODO: should be userSnapshot!
+        const userSnapshot = createUser(user); 
+        console.log(userSnapshot);
+        dispatch(setUser(user)); // TODO: test and use userSnapshot!
       }
     });
 
diff --git a/src/components/button/button.component.jsx b/src/components/button/button.component.jsx
deleted file mode 100644
index a2dca5e..0000000
--- a/src/components/button/button.component.jsx
+++ /dev/null
@@ -1,14 +0,0 @@
-import { BaseButton, GoogleSignInButton, InvertedButton, SpinnerButton } from './button.sytles'
-
-const getButton = (buttonType = 'base') => ({
-    base: BaseButton,
-    google: GoogleSignInButton,
-    inverted: InvertedButton,
-}[buttonType])
-
-const Button = ({ children, buttonType, isLoading, ...otherProps }) => {
-    const CustomButton = getButton(buttonType);
-    return <CustomButton {...otherProps}>{isLoading ? <SpinnerButton /> : children}</CustomButton>;
-};
-
-export default Button;
\ No newline at end of file
diff --git a/src/components/button/button.component.tsx b/src/components/button/button.component.tsx
new file mode 100644
index 0000000..e5f024e
--- /dev/null
+++ b/src/components/button/button.component.tsx
@@ -0,0 +1,26 @@
+import { ButtonHTMLAttributes, FC } from 'react';
+import { BaseButton, GoogleSignInButton, InvertedButton, SpinnerButton } from './button.sytles'
+
+export enum BUTTON_TYPES {
+    base = 'base',
+    google = 'google',
+    inverted = 'inverted',
+};
+
+const getButton = (buttonType = BUTTON_TYPES.base): typeof BaseButton => ({
+    [BUTTON_TYPES.base]: BaseButton,
+    [BUTTON_TYPES.google]: GoogleSignInButton,
+    [BUTTON_TYPES.inverted]: InvertedButton,
+}[buttonType])
+
+export type ButtonProps = {
+    buttonType?: BUTTON_TYPES,
+    isLoading?: boolean,
+} & ButtonHTMLAttributes<HTMLButtonElement>;
+
+const Button: FC<ButtonProps> = ({ children, buttonType, isLoading, ...otherProps }) => {
+    const CustomButton = getButton(buttonType);
+    return <CustomButton {...otherProps}>{isLoading ? <SpinnerButton /> : children}</CustomButton>;
+};
+
+export default Button;
\ No newline at end of file
diff --git a/src/components/button/button.sytles.jsx b/src/components/button/button.sytles.tsx
similarity index 100%
rename from src/components/button/button.sytles.jsx
rename to src/components/button/button.sytles.tsx
diff --git a/src/components/payment-form/payment-form.component.jsx b/src/components/payment-form/payment-form.component.jsx
index 073307d..80bb956 100644
--- a/src/components/payment-form/payment-form.component.jsx
+++ b/src/components/payment-form/payment-form.component.jsx
@@ -1,7 +1,6 @@
 import { useState } from 'react';
 import { CardElement, useStripe, useElements } from '@stripe/react-stripe-js';
-import Button from '../button/button.component';
-import { PaymentFormContainer, FormContainer } from './payment-form.styles';
+import { PaymentFormContainer, FormContainer, PaymentButton } from './payment-form.styles';
 import { useSelector } from 'react-redux';
 
 const PaymentForm = () => {
@@ -52,13 +51,13 @@ const PaymentForm = () => {
       <FormContainer>
         <h2>Credit Card Payment: </h2>
         <CardElement />
-        <Button 
+        <PaymentButton 
           isLoading={isPaymentProcessing}
           buttonType='inverted' 
           onClick={paymentHandler}
         >
             Pay Now
-        </Button>
+        </PaymentButton>
       </FormContainer>
     </PaymentFormContainer>
   )
diff --git a/src/components/payment-form/payment-form.styles.jsx b/src/components/payment-form/payment-form.styles.jsx
index ed63cff..c9ad222 100644
--- a/src/components/payment-form/payment-form.styles.jsx
+++ b/src/components/payment-form/payment-form.styles.jsx
@@ -1,4 +1,5 @@
 import styled from "styled-components";
+import Button from "../button/button.component";
 
 export const PaymentFormContainer = styled.div`
   height: 300px;
@@ -12,3 +13,8 @@ export const FormContainer = styled.div`
   height: 100px;
   min-width: 500px;
 `;
+
+export const PaymentButton = styled(Button)`
+  margin-left: auto;
+  margin-top: 30px;
+`
diff --git a/src/components/sign-in-form/sign-in-form.component.jsx b/src/components/sign-in-form/sign-in-form.component.jsx
index 62a51b2..1a8d6b9 100644
--- a/src/components/sign-in-form/sign-in-form.component.jsx
+++ b/src/components/sign-in-form/sign-in-form.component.jsx
@@ -2,7 +2,7 @@ import { useState } from 'react';
 import { signInWithGooglePopup } from '../../utils/firebase/firebase.utils';
 import { signInAuthUserWithEmailAndPassword } from '../../utils/firebase/firebase.utils';
 import FormInput from '../../components/form-input/form-input.component';
-import Button from '../../components/button/button.component';
+import Button from '../button/button.component';
 import { SignInContainer, ButtonContainer } from './sign-in-form.styles'
 
 const defaultFormFields = {
@@ -66,8 +66,8 @@ const SignInForm = ()=> {
                 value={password}
             />
             <ButtonContainer>
-                <Button>Sign In</Button>
-                <Button type="button" onClick={LogGoogleUser} buttonType="google">
+                <Button buttonType="inverted">Sign In</Button>
+                <Button onClick={LogGoogleUser} buttonType="google">
                     Google Sign In
                 </Button>
             </ButtonContainer>
diff --git a/src/components/sign-up-form/sign-up-form.component.jsx b/src/components/sign-up-form/sign-up-form.component.jsx
index f010503..0dfb9f7 100644
--- a/src/components/sign-up-form/sign-up-form.component.jsx
+++ b/src/components/sign-up-form/sign-up-form.component.jsx
@@ -1,7 +1,7 @@
 import { useState } from 'react';
 import { createAuthUserWithEmailAndPassword } from '../../utils/firebase/firebase.utils';
 import FormInput from '../../components/form-input/form-input.component';
-import Button from '../../components/button/button.component';
+import Button from '../button/button.component';
 import { SignUpContainer } from './sign-up-form.styles';
 
 const defaultFormFields = {
@@ -73,7 +73,7 @@ const SignUpForm = ()=> {
                 onChange={handleChange} 
                 value={confirmPassword}
             />
-            <Button buttonType="google">Sign Up</Button>
+            <Button buttonType="base">Sign Up</Button>
         </form>
     </SignUpContainer>
     )
diff --git a/src/store/categories/categories.slice.js b/src/store/categories/categories.slice.ts
similarity index 61%
rename from src/store/categories/categories.slice.js
rename to src/store/categories/categories.slice.ts
index 2ac074c..61a71a1 100644
--- a/src/store/categories/categories.slice.js
+++ b/src/store/categories/categories.slice.ts
@@ -1,6 +1,14 @@
 import { createSlice } from "@reduxjs/toolkit";
+import type { PayloadAction } from '@reduxjs/toolkit'
+import { RootState } from "../store";
 
-const InitCategoriesSate = {
+interface CategoriesState {
+    categoriesMap: Object | null,
+    isLoading: boolean,
+    error: Error | null,
+}
+
+const InitCategoriesSate: CategoriesState = {
     categoriesMap: null,
     isLoading: false,
     error: null
@@ -15,12 +23,12 @@ export const categoriesSlice = createSlice({
             state.error = null;
         },
         // getCategoriesSucceeded
-        setCategories: (state, action) => {
+        setCategories: (state, action: PayloadAction<Object>) => {
             state.categoriesMap = action.payload;
             state.isLoading = false;
             state.error = null;
         },
-        getCategoriesFailed: (state, action) => {
+        getCategoriesFailed: (state, action: PayloadAction<Error>) => {
             state.isLoading = false;
             state.error = action.payload;
         },
@@ -28,4 +36,5 @@ export const categoriesSlice = createSlice({
 });
 
 export const { getCategoriesStart, setCategories, getCategoriesFailed } = categoriesSlice.actions;
+export const selectCategoriesMap = (state: RootState) => state.categories.categoriesMap;
 export default categoriesSlice.reducer;
\ No newline at end of file
diff --git a/src/store/store.js b/src/store/store.ts
similarity index 85%
rename from src/store/store.js
rename to src/store/store.ts
index e3a8c66..a69f348 100644
--- a/src/store/store.js
+++ b/src/store/store.ts
@@ -47,6 +47,11 @@ export const store = configureStore({
   devTools: process.env.NODE_ENV !== 'production', // The Redux DevTools Extension is disabled for production
 });
 
+// Infer the `RootState` and `AppDispatch` types from the store itself
+export type RootState = ReturnType<typeof store.getState>;
+// Inferred type: {posts: PostsState, comments: CommentsState, users: UsersState}
+export type AppDispatch = typeof store.dispatch;
+
 // then run the saga
 sagaMiddleware.run(rootSaga)
 
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..ed63278
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "noFallthroughCasesInSwitch": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react-jsx"
+  },
+  "include": ["src"]
+}
\ No newline at end of file
diff --git a/yarn.lock b/yarn.lock
index a956e98..d96890d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2522,7 +2522,7 @@
   dependencies:
     "@types/node" "*"
 
-"@types/hoist-non-react-statics@^3.3.1":
+"@types/hoist-non-react-statics@*", "@types/hoist-non-react-statics@^3.3.1":
   version "3.3.1"
   resolved "https://registry.npmmirror.com/@types/hoist-non-react-statics/-/hoist-non-react-statics-3.3.1.tgz#1124aafe5118cb591977aeb1ceaaed1070eb039f"
   integrity sha512-iMIqiko6ooLrTh1joXodJK5X9xeEALT1kM5G3ZLhD3hszxBdIEd5C75U834D9mLcINgD4OyZf5uQXjkuYydWvA==
@@ -2569,6 +2569,14 @@
     expect "^29.0.0"
     pretty-format "^29.0.0"
 
+"@types/jest@^29.2.5":
+  version "29.2.5"
+  resolved "https://registry.npmmirror.com/@types/jest/-/jest-29.2.5.tgz#c27f41a9d6253f288d1910d3c5f09484a56b73c0"
+  integrity sha512-H2cSxkKgVmqNHXP7TC2L/WUorrZu8ZigyRywfVzv6EyBlxj39n4C00hjXYQWsbwqgElaj/CiAeSRmk5GoaKTgw==
+  dependencies:
+    expect "^29.0.0"
+    pretty-format "^29.0.0"
+
 "@types/json-schema@*", "@types/json-schema@^7.0.4", "@types/json-schema@^7.0.5", "@types/json-schema@^7.0.8", "@types/json-schema@^7.0.9":
   version "7.0.11"
   resolved "https://registry.npmmirror.com/@types/json-schema/-/json-schema-7.0.11.tgz#d421b6c527a3037f7c84433fd2c4229e016863d3"
@@ -2599,7 +2607,7 @@
   resolved "https://registry.npmmirror.com/@types/node/-/node-18.11.10.tgz#4c64759f3c2343b7e6c4b9caf761c7a3a05cee34"
   integrity sha512-juG3RWMBOqcOuXC643OAdSA525V44cVgGV6dUDuiFtss+8Fk5x1hI93Rsld43VeJVIeqlP9I7Fn9/qaVqoEAuQ==
 
-"@types/node@>=8.1.0":
+"@types/node@>=8.1.0", "@types/node@^18.11.18":
   version "18.11.18"
   resolved "https://registry.npmmirror.com/@types/node/-/node-18.11.18.tgz#8dfb97f0da23c2293e554c5a50d61ef134d7697f"
   integrity sha512-DHQpWGjyQKSHj3ebjFI/wRKcqQcdR+MoFBygntYOZytCqNfkd2ZC4ARDJ2DQqhjH5p85Nnd3jhUJIXrszFX/JA==
@@ -2641,6 +2649,13 @@
   dependencies:
     "@types/react" "*"
 
+"@types/react-dom@^18.0.10":
+  version "18.0.10"
+  resolved "https://registry.npmmirror.com/@types/react-dom/-/react-dom-18.0.10.tgz#3b66dec56aa0f16a6cc26da9e9ca96c35c0b4352"
+  integrity sha512-E42GW/JA4Qv15wQdqJq8DL4JhNpB3prJgjgapN3qJT9K2zO5IIAQh4VXvCEDupoqAwnz0cY4RlXeC/ajX5SFHg==
+  dependencies:
+    "@types/react" "*"
+
 "@types/react@*":
   version "18.0.25"
   resolved "https://registry.npmmirror.com/@types/react/-/react-18.0.25.tgz#8b1dcd7e56fe7315535a4af25435e0bb55c8ae44"
@@ -2650,6 +2665,15 @@
     "@types/scheduler" "*"
     csstype "^3.0.2"
 
+"@types/react@^18.0.26":
+  version "18.0.26"
+  resolved "https://registry.npmmirror.com/@types/react/-/react-18.0.26.tgz#8ad59fc01fef8eaf5c74f4ea392621749f0b7917"
+  integrity sha512-hCR3PJQsAIXyxhTNSiDFY//LhnMZWpNNr5etoCqx/iUfGc5gXWtQR2Phl908jVR6uPXacojQWTg4qRpkxTuGug==
+  dependencies:
+    "@types/prop-types" "*"
+    "@types/scheduler" "*"
+    csstype "^3.0.2"
+
 "@types/resolve@1.17.1":
   version "1.17.1"
   resolved "https://registry.npmmirror.com/@types/resolve/-/resolve-1.17.1.tgz#3afd6ad8967c77e4376c598a82ddd58f46ec45d6"
@@ -2699,6 +2723,15 @@
   resolved "https://registry.npmmirror.com/@types/stack-utils/-/stack-utils-2.0.1.tgz#20f18294f797f2209b5f65c8e3b5c8e8261d127c"
   integrity sha512-Hl219/BT5fLAaz6NDkSuhzasy49dwQS/DSdu4MdggFB8zcXv7vflBI3xp7FEmkmdDkBUI2bPUNeMttp2knYdxw==
 
+"@types/styled-components@^5.1.26":
+  version "5.1.26"
+  resolved "https://registry.npmmirror.com/@types/styled-components/-/styled-components-5.1.26.tgz#5627e6812ee96d755028a98dae61d28e57c233af"
+  integrity sha512-KuKJ9Z6xb93uJiIyxo/+ksS7yLjS1KzG6iv5i78dhVg/X3u5t1H7juRWqVmodIdz6wGVaIApo1u01kmFRdJHVw==
+  dependencies:
+    "@types/hoist-non-react-statics" "*"
+    "@types/react" "*"
+    csstype "^3.0.2"
+
 "@types/testing-library__jest-dom@^5.9.1":
   version "5.14.5"
   resolved "https://registry.npmmirror.com/@types/testing-library__jest-dom/-/testing-library__jest-dom-5.14.5.tgz#d113709c90b3c75fdb127ec338dad7d5f86c974f"
@@ -9470,6 +9503,11 @@ typescript-tuple@^2.2.1:
   dependencies:
     typescript-compare "^0.0.2"
 
+typescript@^4.9.4:
+  version "4.9.4"
+  resolved "https://registry.npmmirror.com/typescript/-/typescript-4.9.4.tgz#a2a3d2756c079abda241d75f149df9d561091e78"
+  integrity sha512-Uz+dTXYzxXXbsFpM86Wh3dKCxrQqUcVMxwU54orwlJjOpO3ao8L7j5lH+dWfTwgCwIuM9GQ2kvVotzYJMXTBZg==
+
 unbox-primitive@^1.0.2:
   version "1.0.2"
   resolved "https://registry.npmmirror.com/unbox-primitive/-/unbox-primitive-1.0.2.tgz#29032021057d5e6cdbd08c5129c226dff8ed6f9e"