Javascript node.js无法读取属性';长度';未定义的;在Object.username
我试图在node.js中创建用户/通过验证程序,但我没有经验,因此收到以下错误: TypeError:无法读取未定义的属性长度;位于Object.username(C:\Users\61468\Desktop\WebServer\validation.js:2:18) 我尝试了username/password.value并尝试了字符串,但我被卡住了。非常感谢您的帮助Javascript node.js无法读取属性';长度';未定义的;在Object.username,javascript,node.js,mongodb,Javascript,Node.js,Mongodb,我试图在node.js中创建用户/通过验证程序,但我没有经验,因此收到以下错误: TypeError:无法读取未定义的属性长度;位于Object.username(C:\Users\61468\Desktop\WebServer\validation.js:2:18) 我尝试了username/password.value并尝试了字符串,但我被卡住了。非常感谢您的帮助 const express = require("express"); const router = exp
const express = require("express");
const router = express.Router();
const db = require("../../mongo").db();
const validate = require("../../validation");
const mongo = require("../../mongo");
router.post("/register", (req, res) => {
let {username, email, password} = req.body;
let err = validate.username(username);
if(err) throw err;
err = validate.password(password);
if(err) throw err;
mongo.collection(users).insert({ "username": username, "password": password }).then((err, res) => {
res.send("I just registered");
if(err) throw err;
})
});
module.exports = router;
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>WebServer</title>
<script>
function register() {
let data = {
username: document.querySelector("#user").value,
pass: document.querySelector("#pass").value,
}
fetch("/api/register", {
method: "POST",
body: JSON.stringify(data),
}).then((res) => {
console.log(res.json());
});
}
</script>
</head>
<body>
<h1>Register:</h1>
<input id = "user" placeholder="username">
<input id = "pass" type = "password"placeholder="password">
<button onclick="register()">Register</button>
</body>
</html>
function username(username) {
if (username.length < 3) {
return "Username cannot be less than 3 characters!";
} else if (username.length > 15){
return "Username cannot be longer than 15 characters!";
}
return "";
}
function password(password) {
if (password.length < 8) {
return "Password cannot be less than 8 characters!";
} else if (password.length > 20){
return "Password cannot be longer than 20 characters!";
}
return "";
}
module.exports = {
username,
password
}
const express=require(“express”);
const router=express.router();
const db=require(“../../mongo”).db();
const validate=require(“../../validation”);
const mongo=require(“../../mongo”);
路由器.post(“/寄存器)”,(请求,res)=>{
让{username,email,password}=req.body;
让err=validate.username(用户名);
如果(错误)抛出错误;
err=validate.password(密码);
如果(错误)抛出错误;
集合(用户)。插入({“username”:username,“password”:password})。然后((err,res)=>{
res.send(“我刚刚注册”);
如果(错误)抛出错误;
})
});
module.exports=路由器;
网络服务器
函数寄存器(){
让数据={
用户名:document.querySelector(“#user”).value,
通过:document.querySelector(“#通过”).value,
}
获取(“/api/寄存器”{
方法:“张贴”,
正文:JSON.stringify(数据),
})。然后((res)=>{
log(res.json());
});
}
登记册:
登记
函数用户名(username){
如果(username.length<3){
return“用户名不能少于3个字符!”;
}否则如果(username.length>15){
return“用户名不能超过15个字符!”;
}
返回“”;
}
功能密码(密码){
如果(密码长度<8){
return“密码不能少于8个字符!”;
}否则如果(password.length>20){
return“密码不能超过20个字符!”;
}
返回“”;
}
module.exports={
用户名,
密码
}
如果需要答案,则需要重命名函数
如果它不起作用,那么你需要尝试一下
在函数中添加条件,如
function password(password) {
if (password && password!=undefined && password.length < 8) {
return "Password cannot be less than 8 characters!";
} else if (password && password!=undefined &&password.length > 20){
return "Password cannot be longer than 20 characters!";
}
return "";
}
功能密码(密码){
if(password&&password!=未定义&&password.length<8){
return“密码不能少于8个字符!”;
}else if(password&&password!=未定义&&password.length>20){
return“密码不能超过20个字符!”;
}
返回“”;
}
像这样。如果您需要答案,那么您需要重命名您的函数 如果它不起作用,那么你需要尝试一下 在函数中添加条件,如
function password(password) {
if (password && password!=undefined && password.length < 8) {
return "Password cannot be less than 8 characters!";
} else if (password && password!=undefined &&password.length > 20){
return "Password cannot be longer than 20 characters!";
}
return "";
}
功能密码(密码){
if(password&&password!=未定义&&password.length<8){
return“密码不能少于8个字符!”;
}else if(password&&password!=未定义&&password.length>20){
return“密码不能超过20个字符!”;
}
返回“”;
}
类似于此。您的参数与函数的调用方式相同。尝试重命名函数或参数。也就是说,
函数validateUsername(username).
您的参数与函数调用的内容相同。尝试重命名函数或参数。例如,函数validateUsername(用户名).