<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>let 的基本使用</title>
<script type="text/javascript">
let name = "Tom 哇嘎";
console.log("name=", name); //使用+, 字符串的拼接, 如果 name 是一个对象, 会输出 object, 而不会输出对象的完整信息
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>const 的基本使用</title>
<script type="text/javascript">
/**老韩解读
1. 常量在定义时，需要赋值
2. 常量赋值后不能修改
*/
const PI = 3.14;
console.log("PI=", PI)
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>数组解构学习 </title>
<script type="text/javascript">
let arr = [1, 2, 3];
//数组解构[取出元素]
//1.传统
let x = arr[0], y = arr[1], z = arr[2];
console.log(x, y, z);
//2. ES6 风格
let [a, b, c] = arr;
console.log("==================================");
console.log(a, b, c);
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>对象解构</title>
<script type="text/javascript">
let monster = {name: '牛魔王', age: 800};
//传统方式取出属性-解构 对象名.属性名
console.log(monster.name, " ", monster.age);
//ES6 对象解构
/*
* 细节解读
* {name,age} 的取名 name 和 age 要和 monster 对象的属性名保持一致
* 使用{} 包括, 不要使用[]
* . {name,age} 顺序是无所谓
* */
let {name, age} = monster;
console.log("========================");
console.log("name=", name, " age=", age);
//还有其它的形式,比如方法上使用对象解构
//如果这样使用，仍然要保证名称和对象的属性名一致
function f1({name, age}) {
console.log("f1-name=", name, " ", "f1-age=", age)
}
f1(monster);
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>模板字符串的演示</title>
<script type="text/javascript">
let name = "hspedu 教育";
//(1) 当解析 ${name}, 就找最近的 name 遍历, 进行替换
//(2) 然后可以得到最后解析的字符串
let str2 = `教育名称=${name}`;
let str3 = `1+2=${1 + 2}`;
// 字符串中调用函数
function sayHi(name) {
return "hi " + name;
}
let name2 = "tom";
let str5 = `sayHi() 返回的结果是=${sayHi('jack')}`;
let str6 = `sayHi() 返回的结果是=${sayHi(name2)}`;
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>声明对象的简写方式</title>
<script type="text/javascript">
const age = 800;
const name = "牛魔王";
// 传统 声明/定义对象
let monster = {name: name, age: age};
// ES6 声明/定义对象
//老师解读
//1. {name, age} : 表示对象的属性名是 name 和 age
//2. 属性 name 的值是从变量/常量 name 来的
let monster02 = {name, age};
console.log("monster02=>", monster02);
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>对象方法的简写形式</title>
<script type="text/javascript">
// 传统-对象方法定义
let monster = {
name: "红孩儿", age: 100,
sayHi: function () {
console.log("信息: name=", this.name, " age=", this.age);
}
}
monster.f10 = function () {
console.log("哈哈");
};
monster.sayHi();
monster.f10();
// ES6-对象方法定义
let monster2 = {
name: "红孩儿~", age: 900,
sayHi() {
console.log("信息: name=", this.name, " age=", this.age);
},
f1() {
console.log("f1()");
}
}
monster2.sayHi();
monster2.f1();
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>对象拓展运算符</title>
<script type="text/javascript">
let cat = {name: "小花猫", age: 2};
// let cat2 = cat;
// cat2.name = "大花猫";
// console.log("cat=>", cat);
// console.log("cat2=>", cat2);//
// 拷贝对象(深拷贝)
let cat2 = {...cat};
cat2.name = "中花猫";
console.log("cat=>", cat);//小花猫
console.log("cat2=>", cat2);//中花猫
// 合并对象[深拷贝]
let monster = {name: "白骨精", age: 100};
let car = {brand: "奔驰", price: 800000};
let monster_car = {...monster, ...car}
monster_car.name = "狐狸精";
console.log("monster=>", monster);
console.log("monster_car=>", monster_car);
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>箭头函数的使用</title>
<script type="text/javascript">
// 传统定义函数
var f1 = function (n) {
return n * 2
}
console.log("传统= " + f1(2)) //传统= 4
// ES6 , 箭头函数使用
let f2 = (n) => {
return n * 2;
}
console.log("f2() 结果= ", f2(100));//200
//上面的 es6 函数写法，还可以简化
let f3 = n => n * 3;
console.log("f3() 结果=", f3(100));//300
//函数也可以传给一个变量=> 看看 java 基础匿名内部类
function hi(f4) {
console.log(f4(900));
}
hi((n) => { //1000
return n + 100
});
hi((n) => {
return n - 100 //800
});
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>箭头函数的使用2</title>
<script type="text/javascript">
// 传统
var f1 = function (n, m) {
var res = 0
for (var i = n; i <= m; i++) {
res += i
}
return res
}
console.log("传统= " + f1(1, 10))
// ES6 , 箭头函数使用
let f2 = (n, m) => {
var res = 0
for (var i = n; i <= m; i++) {
res += i
}
return res
};
console.log(f2(1, 10));
</script>
}
</head>
<body>
</body>
</html>
箭头函数+对象解构
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>箭头函数+对象解构</title>
<script type="text/javascript">
const monster = {
name: "红孩儿", age: 1000, skill: ['红缨枪', '三位真火']
}
//要求：在方法形参取出 monster 对象的 skill 属性
//传统方式
function f1(monster) {
console.log("skill=", monster.skill);
}
f1(monster);
//箭头函数
let f2 = ({skill}) => {
console.log("skill=", skill);
}
//老韩解读
//1. f2 传入对象 monster
//2. f2 形参是 {skill} , 所以 es6 的对象解构特性, 会把 monster 对象的 skill 属性赋给skill
//3. 对象解构的前提就是 {skill}的 skill 和 monster 的 skill 属性是一致
f2(monster);
//箭头函数+解构, 注意有{}, skill 名称需要和对象属性名一致.
let f3 = ({age, name, skill}) => {
console.log("skill=", skill, " age=", age, " name=", name);
}
f3(monster);
</script>
</head>
<body>
</body>
</html>