私有属性
class Person{
//公有属性
name;
//私有属性
#age;
#weight;
//构造方法
constructor(name, age, weight){
this.name = name;
this.#age = age;
this.#weight = weight;
}
intro(){
console.log(this.name);
console.log(this.#age);
console.log(this.#weight);
}
}
//实例化
const girl = new Person('晓红', 18, '45kg');
// console.log(girl.name);
// console.log(girl.#age);//不能获取私有属性
// console.log(girl.#weight);//不能获取私有属性
girl.intro();//内部可以获取
Promise.allSettled
//声明两个promise对象
const p1 = new Promise((resolve, reject)=>{
setTimeout(()=>{
resolve('商品数据 - 1');
},1000)
});
const p2 = new Promise((resolve, reject)=>{
setTimeout(()=>{
resolve('商品数据 - 2');
// reject('出错啦!');
},1000)
});
//调用 allsettled 方法
const result = Promise.allSettled([p1, p2]);
const res = Promise.all([p1, p2]);
console.log(res);
String.prototype.matchAll
let str = `<ul>
<li>
<a>肖生克的救赎</a>
<p>上映日期: 1994-09-10</p>
</li>
<li>
<a>阿甘正传</a>
<p>上映日期: 1994-07-06</p>
</li>
</ul>`;
//声明正则
const reg = /<li>.*?<a>(.*?)<\/a>.*?<p>(.*?)<\/p>/sg
//调用方法
const result = str.matchAll(reg);
// for(let v of result){
// console.log(v);
// }
const arr = [...result];
console.log(arr);
可选链操作符
// ?.
function main(config){
// const dbHost = config && config.db && config.db.host;
const dbHost = config?.db?.host;
console.log(dbHost);
}
main({
db: {
host:'192.168.1.100',
username: 'root'
},
cache: {
host: '192.168.1.200',
username:'admin'
}
})
动态 import
<body>
<button id="btn">点击</button>
<script src="./js/app.js" type="module"></script>
</body>
//hello.js
export function hello(){
alert('Hello');
}
//app.js
// import * as m1 from "./hello.js";
//获取元素
const btn = document.getElementById('btn');
btn.onclick = function(){
import('./hello.js').then(module => {
module.hello();
});
}
BigInt
//大整形
let n = 521n;
console.log(n, typeof(n));
//函数
let n = 123;
console.log(BigInt(n));
console.log(BigInt(1.2));
//大数值运算
let max = Number.MAX_SAFE_INTEGER;
console.log(max);
console.log(max + 1);
console.log(max + 2);
console.log(BigInt(max))
console.log(BigInt(max) + BigInt(1))
console.log(BigInt(max) + BigInt(2))
globalThis
console.log(globalThis);
