标题图
前言
主要讲解了ES6对字符串的拓展，包括includes，startsWith和endsWith，另外增加了字符串模板。
Start
includes()是否包含startsWith()以什么开头endsWith()以什么结尾
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-字符串</title></head><body>
<script>
let str = "你怎么一直在这"; let res = str.includes('一'); console.log(res); </script></body></html>返回结果为true
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-字符串</title></head><body>
<script>
let str = "你怎么一直在这"; let res = str.startsWith('你'); console.log(res); </script></body></html>返回结果为true
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-字符串</title></head><body>
<script>
let str = "你怎么一直在这"; let res = str.startsWith('你'); if(str.startsWith('你')){
执行语句;
}else if(语句){
执行语句;
}else{
执行语句;
} </script></body></html>str.endsWith();
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-字符串</title></head><body>
<script>
let str = "你怎么一直在这";
alert( str.endsWith('这')); </script></body></html><!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-字符串</title></head><body>
<script>
let mail = '34234@qq.com';
if( mail.endsWith('@qq.com') || main.endsWith('@163.com') ){
alert('输入正确');
}else{
alert('请输入邮箱');
} </script></body></html>字符串模板
<!DOCTYPE html><html><head> <meta charset="UTF-8"> <title>ES6-字符串</title></head><body> <script> let str2 = ` <ul> <li>内容</li> </ul> `; console.log(str2); </script></body></html>
函数的参数
函数的参数，展开运算符：
...
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-函数参数</title></head><body>
<script>
function fun(a,b){ console.log(a,b);
}
fun(1,2); </script></body></html><!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-函数参数</title></head><body>
<script>
function fun(a,b,...args){
console.log(a,b);
console.log(...args);
}
fun(1,2,3,4,5);
fun(1,2); </script></body></html><!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-函数参数</title></head><body>
<script>
let arr = [1,2,3]; function fun(a,b,c){ console.log(a); console.log(b); console.log(c);
}
fun(arr[0],arr[1],arr[2]);
fun(...arr); </script></body></html><!DOCTYPE html><html><head> <meta charset="UTF-8"> <title>ES6-函数参数</title></head><body> <script> let arr = [1,2,3]; let arr1=[4,5,6]; let array=[...arr,...arr1]; console.log(array); </script></body></html>
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>ES6-函数参数</title></head><body>
<script>
function fun(a=1,b=2,c=3){ console.log(a,b,c);
}
fun(); // fun(4,5,6);
</script></body></html>了解函数的arguments对象
arguments为一个对象，类数组
<!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>Document</title></head><body>
<script>
function add(a,b){ return a+b;
} console.log(add(1,2); </script></body></html><!DOCTYPE html><html><head>
<meta charset="UTF-8">
<title>Document</title></head><body>
<script>
function add(){ // console.log( arguments); // 返回对象
return arguments[0] + arguments[1];
}
add(1,2); console.log( add(1,2) ); </script></body></html>js面向对象
// var student = {}; //创建对象var student = new Object();
student.name = "dashu";
student.age = 12;
student.job = "school student";
student.study = function(){
alert("study");
}
student.study();var student = { name : "dashu", age : 12;
job: "school student", study : function(){
alert("study");
}
};
student.study();数据属性
js中的
var student = { name: "dashucoding"}
alert(student.name);var student={};Object.defineProperty(student,"name",{ writable:true, value: "dashucoding"});
alert(student.name);
configurable表示能否通过delete来删除属性值，默认为trueEnumerable表示能否通过for-in来枚举对象的属性值，默认为truewritable表示能否修改属性值，默认为true
设计模式-单例模式
var mask = function(){ document.body.appendChild(document.createElement('div'));
}var obtn = document.getElemetnById("btn");
obtn. = function(){
mask();
}// 单例模式var singleton = function(){ var res; return function(fn){ return res||(res=fn.apply(this,arguments))
}
}();var obtn = document.getElementById("btn");
obtn.=function(){
singleton(function(){ return document.body.appendChild(document.createEelement('div'));
})
}解构赋值
解构赋值为一种表达式，用来获取数据
let arr=[1,2,3];let a = arr[0];let b = arr[1];let c = arr[2];console.log(a,b,c);
let arr = [1,2,3];let [a,b,c] = arr;console.log(a,b,c);
let arr = { a:1, b:2, c:3}let (a,b,c) = arr;// let(a,b,c) = [1,2,3];console(a,b,c);
作者：达叔小生
链接：https://www.jianshu.com/p/41b179bd3d67
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