office-ui-fabric-react/lib-amd/utilities/dateMath/DateMath.js

Reusable React components for building experiences for Office 365.

define(["require", "exports"], function (require, exports) {
    "use strict";
    var DAYS_IN_WEEK = 7;
    var MONTHS_IN_YEAR = 12;
    /**
     * Returns a date offset from the given date by the specified number of days.
     * @param {Date} date - The origin date
     * @param {number} days - The number of days to offset. 'days' can be negative.
     * @return {Date} A new Date object offset from the origin date by the given number of days
     */
    function addDays(date, days) {
        var result = new Date(date.getTime());
        result.setDate(result.getDate() + days);
        return result;
    }
    exports.addDays = addDays;
    /**
     * Returns a date offset from the given date by the specified number of weeks.
     * @param {Date} date - The origin date
     * @param {number} weeks - The number of weeks to offset. 'weeks' can be negative.
     * @return {Date} A new Date object offset from the origin date by the given number of weeks
     */
    function addWeeks(date, weeks) {
        return addDays(date, weeks * DAYS_IN_WEEK);
    }
    exports.addWeeks = addWeeks;
    /**
     * Returns a date offset from the given date by the specified number of months.
     * The method tries to preserve the day-of-month; however, if the new month does not have enough days
     * to contain the original day-of-month, we'll use the last day of the new month.
     * @param {Date} date - The origin date
     * @param {number} months - The number of months to offset. 'months' can be negative.
     * @return {Date} A new Date object offset from the origin date by the given number of months
     */
    function addMonths(date, months) {
        var result = new Date(date.getTime());
        var newMonth = result.getMonth() + months;
        result.setMonth(newMonth);
        // We want to maintain the same day-of-month, but that may not be possible if the new month doesn't have enough days.
        // Loop until we back up to a day the new month has.
        // (Weird modulo math is due to Javascript's treatment of negative numbers in modulo)
        if (result.getMonth() !== ((newMonth % MONTHS_IN_YEAR) + MONTHS_IN_YEAR) % MONTHS_IN_YEAR) {
            result = addDays(result, -result.getDate());
        }
        return result;
    }
    exports.addMonths = addMonths;
    /**
     * Returns a date offset from the given date by the specified number of years.
     * The method tries to preserve the day-of-month; however, if the new month does not have enough days
     * to contain the original day-of-month, we'll use the last day of the new month.
     * @param {Date} date - The origin date
     * @param {number} years - The number of years to offset. 'years' can be negative.
     * @return {Date} A new Date object offset from the origin date by the given number of years
     */
    function addYears(date, years) {
        var result = new Date(date.getTime());
        result.setFullYear(date.getFullYear() + years);
        // We want to maintain the same day-of-month, but that may not be possible if the new month doesn't have enough days.
        // Loop until we back up to a day the new month has.
        // (Weird modulo math is due to Javascript's treatment of negative numbers in modulo)
        if (result.getMonth() !== ((date.getMonth() % MONTHS_IN_YEAR) + MONTHS_IN_YEAR) % MONTHS_IN_YEAR) {
            result = addDays(result, -result.getDate());
        }
        return result;
    }
    exports.addYears = addYears;
    /**
     * Returns a date that is a copy of the given date, aside from the month changing to the given month.
     *  The method tries to preserve the day-of-month; however, if the new month does not have enough days
     * to contain the original day-of-month, we'll use the last day of the new month.
     * @param {Date} date - The origin date
     * @param {number} month - The 0-based index of the month to set on the date.
     * @return {Date} A new Date object with the given month set.
     */
    function setMonth(date, month) {
        return addMonths(date, month - date.getMonth());
    }
    exports.setMonth = setMonth;
    /**
     * Compares two dates, and returns true if the two dates (not accounting for time-of-day) are equal.
     * @return {boolean} True if the two dates represent the same date (regardless of time-of-day), false otherwise.
     */
    function compareDates(date1, date2) {
        return (date1.getFullYear() === date2.getFullYear()
            && date1.getMonth() === date2.getMonth()
            && date1.getDate() === date2.getDate());
    }
    exports.compareDates = compareDates;
});