剩余时间计算

   function(endTime) {
const now = new Date().getTime()
            const endTime = new Date(this?.coupon?.endTime || null).getTime()
            const remaining = endTime - now || 0
            if (!remaining || remaining < 0) return ''
            const n2s = (num, unit) => (num ? `${num}${unit}` : '')
            const year = n2s((remaining / 1000 / 60 / 60 / 24 / 30 / 12) | 0, '年')
            const month = n2s((remaining / 1000 / 60 / 60 / 24 / 30) /12 % 12 | 0, '月')
            const day = n2s((remaining / 1000 / 60 / 60 / 24) % 24 | 0, '天')
            const hour = n2s((remaining / 1000 / 60 / 60) % 24 | 0, '小时')
            const minutes = n2s((remaining / 1000) / 60 % 60 | 0, '分钟')
            const text = `${year}${month}${day}${hour}${minutes}`
            return text ? `还剩${text}` : ''
}