js格式化友好的日期显示函数

function friendlyDate(timestamp) {
    var formats = {
        'year': '%n% 年前',
        'month': '%n% 月前',
        'day': '%n% 天前',
        'hour': '%n% 小时前',
        'minute': '%n% 分钟前',
        'second': '%n% 秒前',
    };

    var now = Date.now();
    var seconds = Math.floor((now - timestamp) / 1000);
    var minutes = Math.floor(seconds / 60);
    var hours = Math.floor(minutes / 60);
    var days = Math.floor(hours / 24);
    var months = Math.floor(days / 30);
    var years = Math.floor(months / 12);

    var diffType = '';
    var diffValue = 0;
    if (years > 0) {
        diffType = 'year';
        diffValue = years;
    } else {
        if (months > 0) {
            diffType = 'month';
            diffValue = months;
        } else {
            if (days > 0) {
                diffType = 'day';
                diffValue = days;
            } else {
                if (hours > 0) {
                    diffType = 'hour';
                    diffValue = hours;
                } else {
                    if (minutes > 0) {
                        diffType = 'minute';
                        diffValue = minutes;
                    } else {
                        diffType = 'second';
                        diffValue = seconds === 0 ? (seconds = 1) : seconds;
                    }
                }
            }
        }
    }
    return formats[diffType].replace('%n%', diffValue);
}