JavaScript 控制语句详解与前端服务器搭建指南

let father = {name:'张三', age:18, study:function(){}};
 
for(const n in father) {
    console.log(n);
}

let son = Object.create(father);
son.sex = "男";
 
for(const n in son) {
    console.log(n);
}

for(const n in son) {
    console.log(n, son[n]);
}

let a1 = [1,2,3];
 
for(const i of a1) {
    console.log(i);
}
 
let a2 = [
    {name:'张三', age:18},
    {name:'李四', age:20},
    {name:'王五', age:22}
];
 
for(const obj of a2) {
    console.log(obj.name, obj.age);
}
 
for(const {name,age} of a2) {
    console.log(name, age);
}

let stu1 = {name:'张三', age:18, address: {city:'北京'}};
let stu2 = {name:'张三', age:18};
 
function test(stu) {
    try {
        console.log(stu.address.city)   
    } catch(e) {
        console.log('出现了异常', e.message)
    } finally {
        console.log('finally');
    }
}

nvm node_mirror http://npm.taobao.org/mirrors/node/
nvm npm_mirror https://npm.taobao.org/mirrors/npm/

nvm list available

nvm install 16.16.0

nvm use 16.16.0

npm get registry

npm config set registry https://registry.npm.taobao.org/

npm install express --save-dev

{
  "type": "module",
  "devDependencies": {
    "express": "^4.18.1"
  }
}

node main.js