es6常用简单知识点

1、查询是否包含赢一个字符串
'xxxx'.includes(x,i);//x子字符串，i起始位置
2、forEach（数组的循环不能中断）

array.forEach(function(currentValue,index,array){}) 
//必须 currentValue: 当前的元素
//可选 index：当前元素的索引值
//可选 array: 当前元素所属的数组对象

3、创建类

class Human {
    constructor(name) {
        this.name = name;
    }
    breathe() {
        console.log(this.name + " is breathing");
    }
}
var human = new Human("yancy");
human.breathe();//yancy is breathing

//继承
class Man extends Human {
    constructor(name,sex){
        super(name);//es6语法 访问父级对象上的构造函数
        this.sex = sex;
    }
    info(){
        console.log(`${this.name} is ${this.sex}`);
    }
}
var man = new Man('henry','boy');
man.breathe();//henry is breathing
man.info();//henry is boy

4、箭头函数

var arr = ['A', '', 'B', null, undefined, 'C', '      '];//删掉空字符串
var newArr = arr.filter( val => (val && val.trim()));//newArr = ['A','B','C']