一起来学习Cookie

//服务器端代码
if (path === '/sign_up' && method === 'GET') {
    let string = fs.readFileSync('./sign_up.html', 'utf8')
    response.statusCode = 200
    response.setHeader('Content-Type', 'text/html;charset=utf-8')
    response.write(string)
    response.end()
 }

body, html{height: 100%}
//或者
body{min-height: 100%}
html{height: 100%}
//不能这么写
body, html{min-height: 100%}

body{min-height: 100vh}

//使用jq来写
let hash = {}
let $form = $('#signUpForm')
$form.on('submit', (e) => {
  e.preventDefault() //不用form表单的默认提交，而是使用我们的的ajax提交
  let need = ['email', 'password', 'password_confirmation']
  need.forEach((name) => {
  let value = $form.find(`[name=${name}]`).val()
  hash[name] = value
})

{
  'email': '...',
  'password': '...',
  'password_confirmation': '...'
}

//发起请求之前验证是否为空
if (hash['email'] === '') {
  $form.find('[name="email"]').siblings('.errors').text('请您输入邮箱')
  return false //精髓啊，不然没用了
}
if (hash['password'] === '') {
  $form.find('[name="password"]').siblings('.errors').text('请您输入密码')
  return false //精髓啊，不然没用了
}
if (hash['password_confirmation'] === '') {
    $form.find('[name="password_confirmation"]').siblings('.errors').text('请您再次输入确认密码')
    return false //精髓啊，不然没用了
}
if (hash['password'] !== hash['password_confirmation']) {
  $form.find('[name="password_confirmation"]').siblings('.errors').text('两次输入密码不匹配')
  return false //精髓啊，不然没用了
}

 $form.find('.errors').each((index, span) => {
     $(span).text('')
 })

$.post('/sign_up', hash)
.then((response) => {
  //成功了就打印这个  
  console.log(response)
},
() => {
  //错误了打印这个
})

function readBody(request) {
  return new Promise((resolve, reject) => {
      let body = []
      request.on('data', (chunk) => {
        body.push(chunk)
      }).on('end', () => {
        body = Buffer.concat(body).toString();
          resolve(body)
      })
    }
  )

}

...
if (path === '/sign_up' && method === 'POST') {
    readBody(request).then((body) => {
      let strings = body.split('&') //['email=1', 'password=2', 'password_confirmmation=3']
      let hash = {}
      strings.forEach(string => {
        //想得到类似这种的 string == 'email=1'
        let parts = string.split('=') //再用=分割,得到['email', '1']
        let key = parts[0]
        let value = parts[1]
        hash[key] = decodeURIComponent(value)//hash['email'] = '1'
      })
      let {email, password, password_confirmation} = hash //ES6的解构赋值
  }
  ...

let email = hash['emai']
let password = hash['password']
let password_confirmation = hash['password_confirmation']

let {email, password, password_confirmation} = hash

if (email.indexOf('@') === -1) {
  response.statusCode = 400
  response.write('email is bad') //单引号只是为了标记这是一个字符串
}

console.log(email.indexOf('@'))
console.log(email)

hash[key] = decodeURIComponent(value)

if (email.indexOf('@') === -1) {
  response.statusCode = 400
  response.setHeader('Content-Type', 'application/json;charset=utf-8') //直接告诉浏览器我是json
  response.write(`
    {
      "errors": {
      "email": "invalid"
      }
    }
  `)
}

$.post('/sign_up', hash)
.then((response) => {
  //成功了就打印这个  
  console.log(response)
},
(request, b, c) => {
   console.log(request)
   console.log(b)
   console.log(c)
})

(request) => {
  let {errors} = request.responseJSON    
  if (errors.email && errors.email === 'invalid') {
    $form.find('[name="email"]').siblings('.errors').text('您输入的邮箱错啦')
  }
}

var users = fs.readFileSync('./db/users', 'utf8')
try {
  users = JSON.parse(users) //[] JSON也支持数组
} catch (exception) {
  users = []
}
let inUse = false
for (let i = 0; i < users.length; i++) {
  let user = users[i]
  if (user.email === email) {
    inUse = true
    break
  }
}
if (inUse) {
  response.statusCode = 400
  response.setHeader('Content-Type', 'application/json;charset=utf-8')
  response.write(`
    {
      "errors": {
      "email": "inUse"
      }
    }
  `)
}

if (errors.email && errors.email === 'inUse') {
    $form.find('[name="email"]').siblings('.errors').text('这个邮箱已被注册啦')
}

 users.push({email: email, password: password})//是个对象啊
 var usersString = JSON.stringify(users)
 fs.writeFileSync('./db/users', usersString)
 response.statusCode = 200