openrosa-xpath-evaluator/src/date-extensions.js

Wrapper for browsers' XPath evaluator with added support for OpenRosa extensions.

// imported from https://github.com/enketo/enketo-xpathjs/blob/master/src/date-extensions.js
// TODO probably shouldn't be changing Date.prototype - when these can be safely removed,
// these functions would probably more appropriately be in utils/date.js

/**
 * Consistent with JavaRosa, the following should produce an empty string:
 *
 * - `date('')`
 * - `format-date('')`
 * - `format-date(date(''))`
 *
 * Conversions of `date('')` to a number is still invalid. This behavior
 * deviates from JavaRosa by producing 'Invalid Date' rather than `NaN`,
 * for consistency with historical behavior.
 */
class BlankDate extends Date {
    constructor() {
        super(NaN);
    }

    toString() {
        return '';
    }
}

/**
 * Converts a native Date UTC String to a RFC 3339-compliant date string with local offsets
 * used in ODK, so it replaces the Z in the ISOstring with a local offset
 * @param {Date} date
 * @return {string} a datetime string formatted according to RC3339 with local offset
 */
const toISOLocalString = (date) => {
    // 2012-09-05T12:57:00.000-04:00 (ODK)

    if (['Invalid Date', ''].includes(date.toString())) {
        return date.toString();
    }

    const dt = new Date(date.getTime() - date.getTimezoneOffset() * 60 * 1000)
        .toISOString()
        .replace('Z', getTimezoneOffsetAsTime(date));

    if (dt.indexOf('T00:00:00.000') > 0) {
        return dt.split('T')[0];
    }
    return dt;
};

/**
 * @param {Date} date
 * @return {string}
 */
const getTimezoneOffsetAsTime = (date) => {
    const pad2 = function (x) {
        return x < 10 ? `0${x}` : x;
    };

    if (date.toString() === 'Invalid Date') {
        return date.toString();
    }

    const offsetMinutesTotal = date.getTimezoneOffset();

    const direction = offsetMinutesTotal < 0 ? '+' : '-';
    const hours = pad2(Math.floor(Math.abs(offsetMinutesTotal / 60)));
    const minutes = pad2(Math.floor(Math.abs(offsetMinutesTotal % 60)));

    return `${direction + hours}:${minutes}`;
};

/**
 * @deprecated
 * @see {toISOLocalString}
 */
// eslint-disable-next-line no-extend-native
Date.prototype.toISOLocalString = function () {
    return toISOLocalString(this);
};

/**
 * @deprecated
 * @see {getTimezoneOffsetAsTime}
 */
// eslint-disable-next-line no-extend-native
Date.prototype.getTimezoneOffsetAsTime = function () {
    return getTimezoneOffsetAsTime(this);
};

module.exports = {
    BlankDate,
    getTimezoneOffsetAsTime,
    toISOLocalString,
};