// 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",
        w:  "a week",
        ww: "%d weeks",
        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.

Note: Handling for w and ww was added in 2.25.0.