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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
console.log("-----------------");
// 模板字面量
let num = 3;
let price =10;
str = `商品数量: ${num} 商品价格： ${price}`;
console.log(str);
// 标签函数
function show(zimianliang,val,val1) {
console.log(zimianliang);
str =`${zimianliang}[0] ${val}[0] ${zimianliang}[1] ${val1}[1];`
}
console.log(str);
console.log("-----------------");
const user = {
name : "admin",
passowrd :"qweqwe",
}
let name ="admin";
let passowrd ="qweqwe";
({name,password} =user) ;
console.log(name ,passowrd);//对等属性
({name,passowrd,email} =user);
console.log(name,passowrd,email); //不对等结构
({name,passowrd,email="admim@qq.com"} = user)
console.log(name,email,passowrd);
console.log("-----------------");
let age = 10;
// 单分支
if(age>5){
console.log("青年");
}else{
console.log("儿童");
}
// 多分枝判断
if (age>=10) {
console.log("青年");
}else if (age<=10 && age>=8 ) {
console.log("儿童");
}else {
console.log("妖怪");
}
switch (true){
case age>=10:
console.log("青年");
break;
case age<=10 && age<=8:
console.log("儿童");
}
let agee =( age>=10) ? "青年" :"儿童"; //三元运算符
console.log(agee);
console.log("-----------------");
// wihle循环 入口判断
let arr = ["a","b","c","d","e"];
console.log(arr);
let i =0;
while (i<arr.length) {
console.log(arr[i]);
i++;
}
// do wile循环 出口判断
i =0;
do {
} while (i>arr.length){
console.log("do wihle",arr[i]);
i++;
}
// for 循环
for ( i=0;i<arr.length;i++){
console.log(arr[i]);
}
// for in 遍历对象允许的属性
// 创建对象
const niuge= {
ok:"200",
no:"500",
};
for ( let key in niuge) {
console.log(key,"=>",niuge[key]);
}
// foreach 遍历对象
arr.forEach(function (itme,key,arr) {
console.log( key, "=>",key);
});
console.log("-----for- of 不支持遍历自定义对象----------------");
for (const v of arr) {
console.log(v);
};
// 函数知识
// 声明
function show() {
console.log(name);
}
// 调用
show(niuge);
console.log("--------------");
// 函数的参数
function show1(name) {
console.log(name);
}
show1("牛哥哥");//参数
// 函数默认参数
function show2(status = 1) {
let message;
message = status === 1? "正常" : "错误";
console.log(message);
}
show2(0);
show2(2);
console.log("--------------");
// ...rest:剩余参数打包一个数组
function sum(...arr) {
console.log(arr);
// 累加器初始化
let res = 0;
for (let v of arr) {
res += v;
}
console.log("rest = ", res);
}
sum(1, 2, 3, 4, 5, 6, 7);
// ...spreed,展开参数
function data() {
console.log(arr);
for (let i=0; i<arr.length; i++){
console.log("spreed = ", arr[i]);
}
}
arr = [1,2,3,4,5,6];
data(...arr);
// 函数的返回值 只能返回一个值。
function show3() {
return "hello php.cn";
}
console.log(show3());
// 返回多个值
function show4(){
return {
status:1,
message:"成功",
};
}
console.log(show4().message);
// 返回数组对象
function show5(){
return [
{ id: 1, name: "admin" },
{ id: 2, name: "peter" },
];
}
console.log(show5(),Array.isArray(show5() ? "数组":"对象"));
console.log(show5()[1].name);
// 函数表达式 当成匿名函数，用在回调方法
let show6 =function () {};
console.log(show6);
// 箭头函数 es6才有，简化函数表达式
let show7 =function (name) {
console.log("Hello %c%s", "color:red", name);
};
show7 = (name)=> {
console.log(name);
};
show7 = () => {
let name = "niuge";
console.log(name);
};
show7 = (name) => (console.log(name));
show7("牛哥哥");
</script>
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</html>
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