用JavaScript实现类似微信的时间显示格式转换：将@time（以毫秒为单位）转化为微信时间

// 星期格式转换 0-6：周日到周六
function weekFormat(e, prefix = "周") {
    switch (e) {
        case 0:
            return prefix + "日"
            break;
        case 1:
            return prefix + "一"
            break;
        case 2:
            return prefix + "二"
            break;
        case 3:
            return prefix + "三"
            break;
        case 4:
            return prefix + "四"
            break;
        case 5:
            return prefix + "五"
            break;
        case 6:
            return prefix + "六"
            break;
        default:
            return ""
            break;
    }
}
// 转换今日的时辰格式
function todayTimeFormat(e) {
    if (e >= 0 && e < 7) {
        return "凌晨"
    } else if (e >= 7 && e < 11) {
        return "上午"
    } else if (e >= 11 && e < 13) {
        return "中午"
    } else if (e >= 13 && e < 18) {
        return "下午"
    } else if (e >= 18 && e < 24) {
        return "晚上"
    } else {
        return ""
    }
}

// 是否显示周几
function isShowWeekDay(sub, weekDay) {
    const currentWeekDay = new Date().getDay()
    const dayTime = 1000 * 60 * 60 * 24
    // 1.当前时间与消息时间相差必须大于2天小于7天
    // 2.当前时间距离本周一相差必须大于2天且小于当前距离周一的天数
    // 3.消息时间不可能是0-周日，因为周日没有给后面时间留空间，不会走这里的逻辑，而是走今天的逻辑
    if (sub >= dayTime * 2 && weekDay !== 0 && sub <= dayTime * currentWeekDay) {
        return true
    } else {
        return false
    }
}


// 仿微信时间显示格式转换 @time 时间戳毫秒
function wechatTimeFormat(time) {
    const today = new Date().getTime()
    // 当前时间减去获取到的时间
    const sub = today - time
    const day = 1000 * 60 * 60 * 24
    const timeDate = new Date(time)
    const currentYear = new Date().getFullYear()
    const getYear = new Date(time).getFullYear()
    const HHmm = `${formatTime2("hh", timeDate)}:${formatTime2("mm", timeDate)}`
    const showWeekDay = isShowWeekDay(sub, timeDate.getDay())
    const currentDay = new Date().getDate()
    const getDay = new Date(time).getDate()
    const subDay = currentDay - getDay
    if (currentYear > getYear) {
        return `${formatTime2("yyyy-MM-dd", timeDate)} ${formatTime2("hh:mm", timeDate)}`
        // 上午下午
        return `${formatTime2("yyyy年MM月dd日", timeDate)} ${todayTimeFormat(timeDate.getHours())} ${formatTime2("hh:mm", timeDate)}`
    } else if (showWeekDay) {
        return `${weekFormat(timeDate.getDay())} ${HHmm}`
        //} else if (sub > day && sub < day * 2) {
    } else if (subDay === 1) {
        return `昨天 ${HHmm}`
    } else if (sub <= day) {
        return HHmm
    } else {
        return `${formatTime2("MM-dd", timeDate)} ${formatTime2("hh:mm", timeDate)}`
        // 上午下午
        return `${formatTime2("MM月dd日", timeDate)} ${todayTimeFormat(timeDate.getHours())} ${formatTime2("hh:mm", timeDate)}`
    }
}

function formatTime2(fmt, timestamp) {
    var date = new Date(timestamp) // 兼容safari
    var o = {
        'M+': date.getMonth() + 1,
        'd+': date.getDate(),
        'h+': date.getHours(),
        'm+': date.getMinutes(),
        's+': date.getSeconds(),
        'q+': Math.floor((date.getMonth() + 3) / 3),
        'S': date.getMilliseconds()
    }
    if (/(y+)/.test(fmt)) {
        fmt = fmt.replace(RegExp.$1, (date.getFullYear() + '').substr(4 - RegExp.$1.length))
    }
    for (var k in o) {
        if (new RegExp('(' + k + ')').test(fmt)) {
            fmt = fmt.replace(RegExp.$1, (RegExp.$1.length === 1) ? (o[k]) : (('00' + o[k]).substr(('' + o[k]).length)))
        }
    }
    return fmt
}

module.exports = {
    weekFormat,
    todayTimeFormat,
    isShowWeekDay,
    wechatTimeFormat
}

原文地址：https://www.cnblogs.com/yoona-lin/p/16401037.html