project_directory
+---dist
|   +---index.js
|   +---app.js
+---frontend
|   +---src
|   |   +---App.tsx
|   |   +---index.html
|   |   \---index.tsx
|   +---package-lock.json
|   +---package.json
|   +---tailwind.config.js
|   +---tsconfig.json
|   +---webpack.common.js
|   +---webpack.dev.js
|   \---webpack.prod.js
+---backend
+---src
|   +---index.ts
|   +---app.ts
+---.gitignore
+---package.json
\---README.md

project_directory
+---dist
|   +---index.js
|   +---app.js
+---frontend
|   +---src
|   |   +---auth
|   |   |   +---index.tsx
|   |   |   +---Login.tsx
|   |   |   +---SignUp.tsx
|   |   +---home
|   |   |   +---index.tsx
|   |   |   +---Home.tsx
|   |   +---index.html
|   |   +---index.tsx
|   |   +---App.tsx
|   |   \---SurveyRouter.tsx

npm install mongoose --save

npm install validator
npm i -D @types/validator

import isLength from "validator/lib/isLength";
import isEmail from "validator/lib/isEmail";

export const signup = (req, res) => {
  // 생략
  if (!isLength(name, { min: 2, max: 10 })) {
    return res.status(422).send("이름은 2-10자로 입력해주세요");
  } else if (!isLength(password, { min: 6 })) {
    return res.status(422).send("비밀번호는 6자 이상으로 입력해주세요");
  } else if (!isEmail(email)) {
    return res.status(422).send("유효하지 않은 이메일입니다");
  }
  // 생략
};

npm i bcryptjs
npm i -D @types/bcryptjs

import bcrypt from "bcryptjs";

const hash = await bcrypt.hash(password, 10);
const newUser = await userDb.createUser({
  email,
  password: hash,
});

npm i cookie-parser
npm i -D @types/cookie-parser

// src/app.ts
import cookieParser from "cookie-parser";

app.use(cookieParser());