fix scope issue

src/App.js

@@ -1,4 +1,7 @@
+import React from "react";
+
 import PostList from "./components/PostList";
+
 import "bootstrap/dist/css/bootstrap.min.css";
 import "./App.css";
 

src/Routes.js

@@ -1,4 +1,6 @@
+import React from "react";
 import { BrowserRouter, Switch, Route } from "react-router-dom";
+
 import App from "./App";
 import Navbar from "./components/Navbar";
 import PostCreate from "./components/PostCreate";

src/components/Comment.js

@@ -1,3 +1,4 @@
+import React from "react";
 import { useParams } from "react-router-dom";
 
 import UserService from "../services/user.service";

src/components/CommentForm.js

@@ -1,4 +1,4 @@
-import { useState, useEffect } from "react";
+import React, { useState, useEffect } from "react";
 import { useParams } from "react-router-dom";
 
 import AuthService from "../services/auth.service";

src/components/Comments.js

@@ -1,3 +1,4 @@
+import React from "react";
 import uniqid from "uniqid";
 
 import Comment from "./Comment";

src/components/Login.js

@@ -1,4 +1,4 @@
-import { useState, useRef } from "react";
+import React, { useState, useRef } from "react";
 import Form from "react-validation/build/form";
 import Input from "react-validation/build/input";
 import CheckButton from "react-validation/build/button";

src/components/Navbar.js

@@ -1,4 +1,4 @@
-import { useState, useEffect } from "react";
+import React, { useState, useEffect } from "react";
 import { Link } from "react-router-dom";
 
 import AuthService from "../services/auth.service";

src/components/PostCreate.js

@@ -1,4 +1,4 @@
-import { useState, useEffect } from "react";
+import React, { useState, useEffect } from "react";
 
 import PostForm from "./PostForm";
 import PostFormButtons from "./PostFormButtons";

src/components/PostDetail.js

@@ -1,4 +1,4 @@
-import { useState, useEffect, useCallback } from "react";
+import React, { useState, useEffect, useCallback } from "react";
 import { useParams, Link } from "react-router-dom";
 import Switch from "react-switch";
 

src/components/PostForm.js

@@ -1,3 +1,5 @@
+import React from "react";
+
 const PostCreateForm = (props) => {
   const handleChangeTitle = (e) => {
     e.preventDefault();

src/components/PostFormButtons.js

@@ -1,3 +1,5 @@
+import React from "react";
+
 const PostFormButtons = (props) => {
   const handleClickCancel = (e) => {
     e.preventDefault();

src/components/PostList.js

@@ -1,6 +1,6 @@
 import uniqid from "uniqid";
 
-import { useState, useEffect } from "react";
+import React, { useState, useEffect } from "react";
 
 import AuthService from "../services/auth.service";
 import UserService from "../services/user.service";

src/components/PostListItem.js

@@ -1,4 +1,4 @@
-import { useState, useEffect } from "react";
+import React, { useState, useEffect } from "react";
 import Switch from "react-switch";
 
 import AuthService from "../services/auth.service";

src/components/PostUpdate.js

@@ -1,4 +1,4 @@
-import { useState, useEffect } from "react";
+import React, { useState, useEffect } from "react";
 import { useParams } from "react-router-dom";
 
 import PostForm from "./PostForm";