function _date(number) {// 补全代码// 补全代码let numberDate = new Date(number)//写法一://let res = [numberDate.getFullYear(), + (numberDate.getMonth()+1), numberDate.getDate()].join('-')//return res

function _date(number) {
   //写法一:注意getMonth() 方法根据本地时间返回指定日期的月份(从 0 到 11)。
let numberDate = new Date(number)
let res = [numberDate.getFullYear(), + (numberDate.getMonth() + 1), numberDate.getDate()].join('-')
return res
//写法二:
let numberDate = new Date(number)
return (numberDate.getFullYear() +'-'+ (numberDate.getMonth()+1) +'-'+numberDate.getDate())
//写法三:
//写法三:使用模板字符串
let numberDate = new Date(number)
return ${numberDate.getFullYear()}-${numberDate.getMonth()+1}-${numberDate.getDate()};}
}