relativeTime

// 从 2.12.0 开始
moment.updateLocale('en', {
    relativeTime : Object
});
// 从 2.8.1 至 2.11.2
moment.locale('en', {
    relativeTime : Object
});

// 废弃于 2.8.1
moment.lang('en', {
    relativeTime : Object
});

Locale#relativeTime 应是用于 moment#from 的替换字符串的对象。

moment.updateLocale('en', {
    relativeTime : {
        future: "in %s",
        past:   "%s ago",
        s  : 'a few seconds',
        ss : '%d seconds',
        m:  "a minute",
        mm: "%d minutes",
        h:  "an hour",
        hh: "%d hours",
        d:  "a day",
        dd: "%d days",
        M:  "a month",
        MM: "%d months",
        y:  "a year",
        yy: "%d years"
    }
});

Locale#relativeTime.future 指向未来日期的前缀/后缀，而 Locale#relativeTime.past 则指向过去日期的前缀/后缀。 对于所有其他字符，单个字符指向单数，而双字符指向复数。

如果语言环境需要对令牌进行其他处理，则可以使用以下签名将令牌设置为函数。 该函数应返回一个字符串。

function (number, withoutSuffix, key, isFuture) {
    return string;
}

key 参数指向 Locale#relativeTime 对象中的替换键。（例如 s m mm h 等）

number 参数指向该键的单位数。 对于 m，该数字是分钟数，以此类推。

如果不带后缀显示令牌，则 withoutSuffix 参数将会为 true，如果带后缀显示令牌，则为 false。（之所以使用逻辑倒置，是因为默认的行为是显示后缀。）

如果要使用未来的后缀/前缀，则 isFuture 参数将会为 true，如果要使用过去的前缀/后缀，则为 false。

// From 2.12.0 onward
moment.updateLocale('en', {
    relativeTime : Object
});
// From 2.8.1 to 2.11.2
moment.locale('en', {
    relativeTime : Object
});

// Deprecated in 2.8.1
moment.lang('en', {
    relativeTime : Object
});

Locale#relativeTime should be an object of the replacement strings for moment#from.

moment.updateLocale('en', {
    relativeTime : {
        future: "in %s",
        past:   "%s ago",
        s  : 'a few seconds',
        ss : '%d seconds',
        m:  "a minute",
        mm: "%d minutes",
        h:  "an hour",
        hh: "%d hours",
        d:  "a day",
        dd: "%d days",
        M:  "a month",
        MM: "%d months",
        y:  "a year",
        yy: "%d years"
    }
});

Locale#relativeTime.future refers to the prefix/suffix for future dates, and Locale#relativeTime.past refers to the prefix/suffix for past dates. For all others, a single character refers to the singular, and a double character refers to the plural.

If a locale requires additional processing for a token, it can set the token as a function with the following signature. The function should return a string.

function (number, withoutSuffix, key, isFuture) {
    return string;
}

The key argument refers to the replacement key in the Locale#relativeTime object. (eg. s m mm h, etc.)

The number argument refers to the number of units for that key. For m, the number is the number of minutes, etc.

The withoutSuffix argument will be true if the token will be displayed without a suffix, and false if it will be displayed with a suffix. (The reason for the inverted logic is because the default behavior is to display with the suffix.)

The isFuture argument will be true if it is going to use the future suffix/prefix and false if it is going to use the past prefix/suffix.