<!DOCTYPE html>
<html lang="en">
<head>
? <meta charset="UTF-8">
? <title>Title</title>
</head>
<body>
<!--
1. 指數(shù)運(yùn)算符(冪): **
2. Array.prototype.includes(value) : 判斷數(shù)組中是否包含指定value
-->
<script type="text/javascript">
console.log(2**3);//8
let arr = [1,4,5,6,'abc'];
console.log(arr.includes('a'));//false
console.log(arr.includes('abc'));//true
console.log(arr.includes(4))//true
</script>
</body>
</html>
class
<!DOCTYPE html>
<html lang="en">
<head>
? <meta charset="UTF-8">
? <title>12_class</title>
</head>
<body>
</body>
<!--
1. 通過(guò)class定義類/實(shí)現(xiàn)類的繼承
2. 在類中通過(guò)constructor定義構(gòu)造方法
3. 通過(guò)new來(lái)創(chuàng)建類的實(shí)例
4. 通過(guò)extends來(lái)實(shí)現(xiàn)類的繼承
5. 通過(guò)super調(diào)用父類的構(gòu)造方法
6. 重寫(xiě)從父類中繼承的一般方法
-->
<script type="text/javascript">
// function Person(name,age){
// this.name = name;
// this.age = age;
// }
// let person = new Person('kobe',40);
// console.log(person);
class Person{
//類的構(gòu)造方法 相當(dāng)于Python的__init__
constructor(name,age){
this.name = name;
this.age = age;
}
//類的一般方法
showName(){
console.log('調(diào)用父類的方法')；
console.log(this.name,this.age);
}
}
//子類 Python寫(xiě)法：class StarPerson(Person):
class StarPerson extends Person{
constructor(name,age,salary){
super(name,age);//調(diào)用父類的構(gòu)造方法
this.salary = salary;
}
//父類方法的重寫(xiě)
showName(){
console.log('調(diào)用子類的方法')；
console.log(this.name,this.age,this.salary);
}
}
let person = new Person('kobe',40);
console.log(person);
// person.showName();
let sp = new StarPerson('wade',36,1243254360);
console.log(sp);
sp.showName();
</script>
</html>
字符串?dāng)U展
<!DOCTYPE html>
<html lang="en">
<head>
? <meta charset="UTF-8">
? <title>01_字符串?dāng)U展</title>
</head>
<body>
<!--
1. includes(str) : 判斷是否包含指定的字符串
2. startsWith(str) : 判斷是否以指定字符串開(kāi)頭
3. endsWith(str) : 判斷是否以指定字符串結(jié)尾
4. repeat(count) : 重復(fù)指定次數(shù)
-->
<script type="text/javascript">
let str = 'adfasdawohenfiinwegk';//true
console.log(str.includes('a'));//true
console.log(str.startsWith('a'));//true
console.log(str.endsWith('k'));//true
console.log(str.repeat(3));//重復(fù)三次
</script>
</body>
</html>
數(shù)值的擴(kuò)展
<!DOCTYPE html>
<html lang="en">
<head>
? <meta charset="UTF-8">
? <title>02_數(shù)值擴(kuò)展</title>
</head>
<body>
<!--
1. 二進(jìn)制與八進(jìn)制數(shù)值表示法: 二進(jìn)制用0b, 八進(jìn)制用0o
2. Number.isFinite(i) : 判斷是否是有限大的數(shù)
3. Number.isNaN(i) : 判斷是否是NaN
4. Number.isInteger(i) : 判斷是否是整數(shù)
5. Number.parseInt(str) : 將字符串轉(zhuǎn)換為對(duì)應(yīng)的數(shù)值
6. Math.trunc(i) : 直接去除小數(shù)部分
-->
<script type="text/javascript">
console.log(0b1010);//10
console.log(0o56);//46
console.log(Number.isFinite(123));//true
console.log(Number.isFinite(Infinity));//false
console.log(Number.isNaN(NaN));//true
console.log(Number.isInteger(123));//true
console.log(Number.isInteger(123.456));//false
console.log(Number.isInteger(123.0));//true
console.log(Number.parseInt('123abc456'));//123
console.log(Number.parseInt('a123abc456'));//NaN
console.log(Math.trunc(123.123));//123
</script>
</body>
</html>
數(shù)組的擴(kuò)展
<html lang="en">
<head>
? <meta charset="UTF-8">
? <title>03_數(shù)組擴(kuò)展</title>
</head>
<body>
<button>測(cè)試1</button>
<br>
<button>測(cè)試2</button>
<br>
<button>測(cè)試3</button>
<br>
<!--
1. Array.from(v) : 將偽數(shù)組對(duì)象或可遍歷對(duì)象轉(zhuǎn)換為真數(shù)組
2. Array.of(v1, v2, v3) : 將一系列值轉(zhuǎn)換成數(shù)組
3. find(function(value, index, arr){return true}) : 找出第一個(gè)滿足條件返回true的元素
4. findIndex(function(value, index, arr){return true}) : 找出第一個(gè)滿足條件返回true的元素下標(biāo)
-->
<script type="text/javascript">
let btns = document.getElementsByTagName('button');
Array.from(btns).forEach(function(item,index){
console.log(item);
})
let arr = Array.of(1,4,'abc',true);
console.log(arr);//[1,4,'abc',true]
let arr2 = [2,3,4,2,5,7,3,6,5];
let result = arr2.find(function(item,index){
return item > 4;
})
console.log(result);//5
result = arr2.findIndex(function(item,index){
return item > 4;
})
console.log(result);//4(5的下標(biāo))
</script>
</body>
</html>
對(duì)象擴(kuò)展
<!DOCTYPE html>
<html lang="en">
<head>
? <meta charset="UTF-8">
? <title>04_對(duì)象擴(kuò)展</title>
</head>
<body>
<!--
1. Object.is(v1, v2)
? * 判斷2個(gè)數(shù)據(jù)是否完全相等
2. Object.assign(target, source1, source2..)
? * 將源對(duì)象的屬性復(fù)制到目標(biāo)對(duì)象上
3. 直接操作 __proto__ 屬性
? let obj2 = {};
? obj2.__proto__ = obj1;
-->
<script type="text/javascript">
console.log(0 == -0);//true
console.log(NaN == NaN);//false
console.log(Object.is(0,-0));//false
console.log(Object.is(NaN,NaN));//true
let obj = {};
let obj1 = {username:'iverson',age:43};
let obj2 = {sex:'男'}；
Object.assign(obj,obj1,obj2);
console.log(obj);//{username:'iverson',age:43,sex:'男'};
let obj3 = {};
let obj4 = {money: 5050000};
boj3.__proto__= obj4;
console.log(obj3)
console.log(obj3.money);
</script>
</body>
</html>
