datalab/web/node_modules/moment/src/lib/duration/bubble.js

import absFloor from '../utils/abs-floor';
import absCeil from '../utils/abs-ceil';
import { createUTCDate } from '../create/date-from-array';

export function bubble () {
    var milliseconds = this._milliseconds;
    var days         = this._days;
    var months       = this._months;
    var data         = this._data;
    var seconds, minutes, hours, years, monthsFromDays;

    // if we have a mix of positive and negative values, bubble down first
    // check: https://github.com/moment/moment/issues/2166
    if (!((milliseconds >= 0 && days >= 0 && months >= 0) ||
            (milliseconds <= 0 && days <= 0 && months <= 0))) {
        milliseconds += absCeil(monthsToDays(months) + days) * 864e5;
        days = 0;
        months = 0;
    }

    // The following code bubbles up values, see the tests for
    // examples of what that means.
    data.milliseconds = milliseconds % 1000;

    seconds           = absFloor(milliseconds / 1000);
    data.seconds      = seconds % 60;

    minutes           = absFloor(seconds / 60);
    data.minutes      = minutes % 60;

    hours             = absFloor(minutes / 60);
    data.hours        = hours % 24;

    days += absFloor(hours / 24);

    // convert days to months
    monthsFromDays = absFloor(daysToMonths(days));
    months += monthsFromDays;
    days -= absCeil(monthsToDays(monthsFromDays));

    // 12 months -> 1 year
    years = absFloor(months / 12);
    months %= 12;

    data.days   = days;
    data.months = months;
    data.years  = years;

    return this;
}

export function daysToMonths (days) {
    // 400 years have 146097 days (taking into account leap year rules)
    // 400 years have 12 months === 4800
    return days * 4800 / 146097;
}

export function monthsToDays (months) {
    // the reverse of daysToMonths
    return months * 146097 / 4800;
}