1 扩展对象
1)属性的简洁表示法:
let a = '开始利用简洁'
let obj = {
a:a//老旧写法
a //新写法---属性名和变量名一致,才可以这样写。
}
1-1)属性名用法
如果key为表达式【数组,对象...】
![](https://file.jishuzhan.net/article/1766388405559627777/2c94f52016401218f3011d0688bea45f.webp)
1-2) 方法名称属性:
![](https://file.jishuzhan.net/article/1766388405559627777/c92fedf1f1fc00cc449f1d3c1bb04eda.webp)
1-3) Object.is()
![](https://file.jishuzhan.net/article/1766388405559627777/997da8ecb07c99047277b24155f4ec57.webp)
1-4) object.assign()
![](https://file.jishuzhan.net/article/1766388405559627777/2961f11269774b2fd2ce995b7f19f18f.webp)
1-5)object.keys(),object.values(),object.entries()
![](https://file.jishuzhan.net/article/1766388405559627777/66418e4f75f0e56562ee3601bccd9c3a.webp)
2 数组的扩展
2-1)扩展运算符...
![](https://file.jishuzhan.net/article/1766388405559627777/f09956667bbd3f0e42677e56071d208f.webp)
2-2) 方法Array.form(),Array.of(),find和findIndex,fill()
2-2-1 Array.form():把一个看起来类似于数组的对象,转换为真正的数组。
![](https://file.jishuzhan.net/article/1766388405559627777/7074df3c81d0674efbd5fb6766c2de5b.webp)
2-2-2) Array.of():把一组值转换为数组
![](https://file.jishuzhan.net/article/1766388405559627777/688e9090eb3b6cd867c1a71acfa7130b.webp)
2-2-3) find和findIndex
![](https://file.jishuzhan.net/article/1766388405559627777/c18c38a70ca616212cb0c478af0a0f49.webp)
2-2-4) fill()
![](https://file.jishuzhan.net/article/1766388405559627777/f74d9957c4415736d80f9d90de79bcdd.webp)
![](https://file.jishuzhan.net/article/1766388405559627777/155140263ac05b62b1136047b92175d2.webp)
3 数值方法(Number 和 Math)
![](https://file.jishuzhan.net/article/1766388405559627777/c052a6adf2207213a064e0167174c9f3.webp)
![](https://file.jishuzhan.net/article/1766388405559627777/58f8300dd01557f0f23dae8b0c176302.webp)
![](https://file.jishuzhan.net/article/1766388405559627777/962af7165adfa2d7a4eff0d94579abd3.webp)
4 标签模板(``反引号)
![](https://file.jishuzhan.net/article/1766388405559627777/8f5e409f6b059e5321bd1c09de4260e0.webp)
5 字符串方法(includes(),startsWith(),endsWith()):
![](https://file.jishuzhan.net/article/1766388405559627777/2604144e99b3b1f72963e7d83771951a.webp)