ES6中js新增的扩展运算符

... 扩展运算符能将数组转换为逗号分隔的参数序列

常用方式 数组的合并

const book1 = ['西游记','水浒传']
const book2 = ['三国演义','红楼梦']

//es5写法
const sidabook = book1.concat(book2)
console.log(sidabook) //输出 ['西游记','水浒传','三国演义','红楼梦']


//es6写法
const sidabook = [...book1,...book2]
console.log(sidabook) //输出 ['西游记','水浒传','三国演义','红楼梦']