扩展运算符

扩展运算符

【...】扩展运算符是能将数组转换为逗号分隔的参数序列

声明一个数组

const boys=['a','b','c'];

声明一个函数

function chunwan(){
    console.log(arguments);
}
chunwan(boys);//Array(3),length:1
chunwan(...boys);//length:3 ['a,','b','c']
chunwan('a','b','c')//上面等价于这个

扩展运算符的应用

1.数组的合并

const kuaizi=['王太利','肖央'];
const fenghuang=['曾毅','玲花'];
//const fantasyapple=kuaizi.concat(fenghuang);
const fantasyapple=[...kuaizi,...fenghuang];
console.log(fantasyapple);//[]

2.数组的克隆

const flowers=['E','G','M'];
const grass=[...flowers];//['E','G','M'];
console.log(grass);

3.将伪数组转换为真正的数组

const divs = document.querySelectorAll('div');
const divArr=[...divs];
console.log(divs);//对象
console.log(divArr)//数组[div,div,div]