简单易读版本:

const relativeTimePeriods = [
    [31536000, 'year'],
    [2419200, 'month'],
    [604800, 'week'],
    [86400, 'day'],
    [3600, 'hour'],
    [60, 'minute'],
    [1, 'second']
];

function relativeTime(date, isUtc=true) {
    if (!(date instanceof Date)) date = new Date(date * 1000);
    const seconds = (new Date() - date) / 1000;
    for (let [secondsPer, name] of relativeTimePeriods) {
        if (seconds >= secondsPer) {
            const amount = Math.floor(seconds / secondsPer);
            return `${amount} ${name}${amount ? 's' : ''}s ago`;
        }
    }
    return 'Just now';
}

从现在开始，Unix时间戳参数

function timeSince(ts){
    now = new Date();
    ts = new Date(ts*1000);
    var delta = now.getTime() - ts.getTime();

    delta = delta/1000; //us to s

    var ps, pm, ph, pd, min, hou, sec, days;

    if(delta<=59){
        ps = (delta>1) ? "s": "";
        return delta+" second"+ps
    }

    if(delta>=60 && delta<=3599){
        min = Math.floor(delta/60);
        sec = delta-(min*60);
        pm = (min>1) ? "s": "";
        ps = (sec>1) ? "s": "";
        return min+" minute"+pm+" "+sec+" second"+ps;
    }

    if(delta>=3600 && delta<=86399){
        hou = Math.floor(delta/3600);
        min = Math.floor((delta-(hou*3600))/60);
        ph = (hou>1) ? "s": "";
        pm = (min>1) ? "s": "";
        return hou+" hour"+ph+" "+min+" minute"+pm;
    } 

    if(delta>=86400){
        days = Math.floor(delta/86400);
        hou =  Math.floor((delta-(days*86400))/60/60);
        pd = (days>1) ? "s": "";
        ph = (hou>1) ? "s": "";
        return days+" day"+pd+" "+hou+" hour"+ph;
    }

}

Lokely使用的一个简短版本:

const intervals = [
  { label: 'year', seconds: 31536000 },
  { label: 'month', seconds: 2592000 },
  { label: 'day', seconds: 86400 },
  { label: 'hour', seconds: 3600 },
  { label: 'minute', seconds: 60 },
  { label: 'second', seconds: 1 }
];

function timeSince(date) {
  const seconds = Math.floor((Date.now() - date.getTime()) / 1000);
  const interval = intervals.find(i => i.seconds < seconds);
  const count = Math.floor(seconds / interval.seconds);
  return `${count} ${interval.label}${count !== 1 ? 's' : ''} ago`;
}

function timeSince(date) { var seconds = Math.floor((new Date() - date) / 1000); var interval = seconds / 31536000; if (interval > 1) { return Math.floor(interval) + " years"; } interval = seconds / 2592000; if (interval > 1) { return Math.floor(interval) + " months"; } interval = seconds / 86400; if (interval > 1) { return Math.floor(interval) + " days"; } interval = seconds / 3600; if (interval > 1) { return Math.floor(interval) + " hours"; } interval = seconds / 60; if (interval > 1) { return Math.floor(interval) + " minutes"; } return Math.floor(seconds) + " seconds"; } var aDay = 24*60*60*1000; console.log(timeSince(new Date(Date.now()-aDay))); console.log(timeSince(new Date(Date.now()-aDay*2)));

简单易读版本:

const relativeTimePeriods = [
    [31536000, 'year'],
    [2419200, 'month'],
    [604800, 'week'],
    [86400, 'day'],
    [3600, 'hour'],
    [60, 'minute'],
    [1, 'second']
];

function relativeTime(date, isUtc=true) {
    if (!(date instanceof Date)) date = new Date(date * 1000);
    const seconds = (new Date() - date) / 1000;
    for (let [secondsPer, name] of relativeTimePeriods) {
        if (seconds >= secondsPer) {
            const amount = Math.floor(seconds / secondsPer);
            return `${amount} ${name}${amount ? 's' : ''}s ago`;
        }
    }
    return 'Just now';
}

可读性强且跨浏览器兼容的代码:

@Travis给出的

var DURATION_IN_SECONDS = { epochs: ['year', 'month', 'day', 'hour', 'minute'], year: 31536000, month: 2592000, day: 86400, hour: 3600, minute: 60 }; function getDuration(seconds) { var epoch, interval; for (var i = 0; i < DURATION_IN_SECONDS.epochs.length; i++) { epoch = DURATION_IN_SECONDS.epochs[i]; interval = Math.floor(seconds / DURATION_IN_SECONDS[epoch]); if (interval >= 1) { return { interval: interval, epoch: epoch }; } } }; function timeSince(date) { var seconds = Math.floor((new Date() - new Date(date)) / 1000); var duration = getDuration(seconds); var suffix = (duration.interval > 1 || duration.interval === 0) ? 's' : ''; return duration.interval + ' ' + duration.epoch + suffix; }; alert(timeSince('2015-09-17T18:53:23'));