DateUtils.js

import moment from 'moment';
import 'moment-timezone';
import _ from 'underscore';
import Onyx from 'react-native-onyx';
import ONYXKEYS from '../ONYXKEYS';
import CONST from '../CONST';

let timezone;
Onyx.connect({
    key: ONYXKEYS.MY_PERSONAL_DETAILS,
    callback: (val) => {
        timezone = val ? val.timezone : CONST.DEFAULT_TIME_ZONE.selected;

        // Make sure that if we have a timezone in object format that we're getting the selected timezone name
        // Older timezone formats only include the timezone name, but the newer format also included whether or
        // not the timezone was selected automatically
        if (_.isObject(timezone)) {
            timezone = val.timezone.selected;
        }
    },
});

/**
 * Gets the user's stored time-zone NVP and returns a localized
 * Moment object for the given timestamp
 *
 * @param {String} locale
 * @param {Number} timestamp
 *
 * @returns  {Moment}
 *
 * @private
 */
function getLocalMomentFromTimestamp(locale, timestamp) {
    moment.locale(locale);
    return moment.unix(timestamp).tz(timezone);
}

/**
 * Formats a timestamp to local date and time string
 *
 * e.g.
 *
 * Jan 20 at 5:30 PM          within the past year
 * Jan 20, 2019 at 5:30 PM    anything over 1 year ago
 *
 * @param {String} locale
 * @param {Number} timestamp
 * @param {Boolean} includeTimeZone
 *
 * @returns {String}
 */
function timestampToDateTime(locale, timestamp, includeTimeZone = false) {
    const date = getLocalMomentFromTimestamp(locale, timestamp);
    const tz = includeTimeZone ? ' [UTC]Z' : '';

    return moment(date).calendar({
        sameDay: `[Today at] LT${tz}`,
        nextDay: `[Tomorrow at] LT${tz}`,
        nextWeek: `MMM D [at] LT${tz}`,
        lastDay: `[Yesterday at] LT${tz}`,
        lastWeek: `MMM D [at] LT${tz}`,
        sameElse: `MMM D, YYYY [at] LT${tz}`,
    });
}

/**
 * Converts a timestamp into a localized string representation
 * that's relative to current moment in time.
 *
 * e.g.
 *
 * < 1 minute ago       within the past minute
 * 12 minutes ago       within the past hour
 * 1 hour ago           within the past day
 * 3 days ago           within the past month
 * Jan 20               within the past year
 * Jan 20, 2019         anything over 1 year
 *
 * @param {String} locale
 * @param {Number} timestamp
 *
 * @returns {String}
 */
function timestampToRelative(locale, timestamp) {
    const date = getLocalMomentFromTimestamp(locale, timestamp);

    return moment(date).fromNow();
}

/**
 * @namespace DateUtils
 */
const DateUtils = {
    timestampToRelative,
    timestampToDateTime,
};

export default DateUtils;