calendar()

moment().calendar();
moment().calendar(referenceTime);
moment().calendar(referenceTime, formats);  // 从 2.10.5 开始

日历时间显示相对于给定的 referenceTime 的时间（默认为现在），但与 moment#fromNow 略有不同。

moment#calendar 会根据日期与 referenceTime 的日期（默认为今天）的接近程度，使用不同的字符串格式化日期。

这些字符串是本地化的，可以自定义。

从 2.10.5 开始，moment 支持指定每次调用的日历输出格式：

moment().calendar(null, {
    sameDay: '[今天]',
    nextDay: '[明天]',
    nextWeek: 'dddd',
    lastDay: '[昨天]',
    lastWeek: '[上个] dddd',
    sameElse: 'DD/MM/YYYY'
});

当 moment 与 referenceTime 相距超过一周时，则将 sameElse 用作格式。

注意：从 2.14.0 版本开始，日历的格式参数可以是一个在 moment 上下文中使用单个参数执行的回调：

moment().calendar(null, {
  sameDay: function (now) {
    if (this.isBefore(now)) {
      return '[今天将会发生]';
    } else {
      return '[今天已发生]';
    }
    /* ... */
  }
});

moment().calendar();
moment().calendar(referenceTime);
moment().calendar(referenceTime, formats);  // from 2.10.5

Calendar time displays time relative to a given referenceTime (defaults to now), but does so slightly differently than moment#fromNow.

moment#calendar will format a date with different strings depending on how close to referenceTime's date (today by default) the date is.

These strings are localized, and can be customized.

From 2.10.5 moment supports specifying calendar output formats per invocation:

moment().calendar(null, {
    sameDay: '[Today]',
    nextDay: '[Tomorrow]',
    nextWeek: 'dddd',
    lastDay: '[Yesterday]',
    lastWeek: '[Last] dddd',
    sameElse: 'DD/MM/YYYY'
});

sameElse is used as the format when the moment is more than a week away from the referenceTime

Note: From version 2.14.0 the formats argument to calendar can be a callback that is executed within the moment context with a single argument now:

moment().calendar(null, {
  sameDay: function (now) {
    if (this.isBefore(now)) {
      return '[Will Happen Today]';
    } else {
      return '[Happened Today]';
    }
    /* ... */
  }
});