js 今天/明天时间戳

var MillisecondsADay = 24 * 60 * 60 * 1
//  今日零点时间戳
var timestamp = Math.floor(new Date(new Date().setHours(0, 0, 0, 0)).getTime() / 1000)
// 昨日开始时间戳
var yesterdayStartTime = timestamp - MillisecondsADay
// 昨日结束时间戳
var yesterdayEndTime = timestamp - 1