date-time.js

来自「javascript实现的关于时间线的简单例子。」· JavaScript 代码 · 共 453 行 · 第 1/2 页

    
    var s = o.toString();
    if (s.length > 0 && s.length < 8) {
        var space = s.indexOf(" ");
        if (space > 0) {
            var year = parseInt(s.substr(0, space));
            var suffix = s.substr(space + 1);
            if (suffix.toLowerCase() == "bc") {
                year = 1 - year;
            }
        } else {
            var year = parseInt(s);
        }
            
        var d = new Date(0);
        d.setUTCFullYear(year);
        
        return d;
    }
    
    try {
        return new Date(Date.parse(s));
    } catch (e) {
        return null;
    }
};

/**
 * Rounds date objects down to the nearest interval or multiple of an interval.
 * This method modifies the given date object, converting it to the given
 * timezone if specified.
 * 
 * @param {Date} date the date object to round
 * @param {Number} intervalUnit a constant, integer index specifying an 
 *   interval, e.g. SimileAjax.DateTime.HOUR
 * @param {Number} timeZone a timezone shift, given in hours
 * @param {Number} multiple a multiple of the interval to round by
 * @param {Number} firstDayOfWeek an integer specifying the first day of the
 *   week, 0 corresponds to Sunday, 1 to Monday, etc.
 */
SimileAjax.DateTime.roundDownToInterval = function(date, intervalUnit, timeZone, multiple, firstDayOfWeek) {
    var timeShift = timeZone * 
        SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.HOUR];
        
    var date2 = new Date(date.getTime() + timeShift);
    var clearInDay = function(d) {
        d.setUTCMilliseconds(0);
        d.setUTCSeconds(0);
        d.setUTCMinutes(0);
        d.setUTCHours(0);
    };
    var clearInYear = function(d) {
        clearInDay(d);
        d.setUTCDate(1);
        d.setUTCMonth(0);
    };
    
    switch(intervalUnit) {
    case SimileAjax.DateTime.MILLISECOND:
        var x = date2.getUTCMilliseconds();
        date2.setUTCMilliseconds(x - (x % multiple));
        break;
    case SimileAjax.DateTime.SECOND:
        date2.setUTCMilliseconds(0);
        
        var x = date2.getUTCSeconds();
        date2.setUTCSeconds(x - (x % multiple));
        break;
    case SimileAjax.DateTime.MINUTE:
        date2.setUTCMilliseconds(0);
        date2.setUTCSeconds(0);
        
        var x = date2.getUTCMinutes();
        date2.setTime(date2.getTime() - 
            (x % multiple) * SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.MINUTE]);
        break;
    case SimileAjax.DateTime.HOUR:
        date2.setUTCMilliseconds(0);
        date2.setUTCSeconds(0);
        date2.setUTCMinutes(0);
        
        var x = date2.getUTCHours();
        date2.setUTCHours(x - (x % multiple));
        break;
    case SimileAjax.DateTime.DAY:
        clearInDay(date2);
        break;
    case SimileAjax.DateTime.WEEK:
        clearInDay(date2);
        var d = (date2.getUTCDay() + 7 - firstDayOfWeek) % 7;
        date2.setTime(date2.getTime() - 
            d * SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.DAY]);
        break;
    case SimileAjax.DateTime.MONTH:
        clearInDay(date2);
        date2.setUTCDate(1);
        
        var x = date2.getUTCMonth();
        date2.setUTCMonth(x - (x % multiple));
        break;
    case SimileAjax.DateTime.YEAR:
        clearInYear(date2);
        
        var x = date2.getUTCFullYear();
        date2.setUTCFullYear(x - (x % multiple));
        break;
    case SimileAjax.DateTime.DECADE:
        clearInYear(date2);
        date2.setUTCFullYear(Math.floor(date2.getUTCFullYear() / 10) * 10);
        break;
    case SimileAjax.DateTime.CENTURY:
        clearInYear(date2);
        date2.setUTCFullYear(Math.floor(date2.getUTCFullYear() / 100) * 100);
        break;
    case SimileAjax.DateTime.MILLENNIUM:
        clearInYear(date2);
        date2.setUTCFullYear(Math.floor(date2.getUTCFullYear() / 1000) * 1000);
        break;
    }
    
    date.setTime(date2.getTime() - timeShift);
};

/**
 * Rounds date objects up to the nearest interval or multiple of an interval.
 * This method modifies the given date object, converting it to the given
 * timezone if specified.
 * 
 * @param {Date} date the date object to round
 * @param {Number} intervalUnit a constant, integer index specifying an 
 *   interval, e.g. SimileAjax.DateTime.HOUR
 * @param {Number} timeZone a timezone shift, given in hours
 * @param {Number} multiple a multiple of the interval to round by
 * @param {Number} firstDayOfWeek an integer specifying the first day of the
 *   week, 0 corresponds to Sunday, 1 to Monday, etc.
 * @see SimileAjax.DateTime.roundDownToInterval
 */
SimileAjax.DateTime.roundUpToInterval = function(date, intervalUnit, timeZone, multiple, firstDayOfWeek) {
    var originalTime = date.getTime();
    SimileAjax.DateTime.roundDownToInterval(date, intervalUnit, timeZone, multiple, firstDayOfWeek);
    if (date.getTime() < originalTime) {
        date.setTime(date.getTime() + 
            SimileAjax.DateTime.gregorianUnitLengths[intervalUnit] * multiple);
    }
};

/**
 * Increments a date object by a specified interval, taking into
 * consideration the timezone.
 *
 * @param {Date} date the date object to increment
 * @param {Number} intervalUnit a constant, integer index specifying an 
 *   interval, e.g. SimileAjax.DateTime.HOUR
 * @param {Number} timeZone the timezone offset in hours
 */
SimileAjax.DateTime.incrementByInterval = function(date, intervalUnit, timeZone) {
    timeZone = (typeof timeZone == 'undefined') ? 0 : timeZone;

    var timeShift = timeZone * 
        SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.HOUR];
        
    var date2 = new Date(date.getTime() + timeShift);

    switch(intervalUnit) {
    case SimileAjax.DateTime.MILLISECOND:
        date2.setTime(date2.getTime() + 1)
        break;
    case SimileAjax.DateTime.SECOND:
        date2.setTime(date2.getTime() + 1000);
        break;
    case SimileAjax.DateTime.MINUTE:
        date2.setTime(date2.getTime() + 
            SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.MINUTE]);
        break;
    case SimileAjax.DateTime.HOUR:
        date2.setTime(date2.getTime() + 
            SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.HOUR]);
        break;
    case SimileAjax.DateTime.DAY:
        date2.setUTCDate(date2.getUTCDate() + 1);
        break;
    case SimileAjax.DateTime.WEEK:
        date2.setUTCDate(date2.getUTCDate() + 7);
        break;
    case SimileAjax.DateTime.MONTH:
        date2.setUTCMonth(date2.getUTCMonth() + 1);
        break;
    case SimileAjax.DateTime.YEAR:
        date2.setUTCFullYear(date2.getUTCFullYear() + 1);
        break;
    case SimileAjax.DateTime.DECADE:
        date2.setUTCFullYear(date2.getUTCFullYear() + 10);
        break;
    case SimileAjax.DateTime.CENTURY:
        date2.setUTCFullYear(date2.getUTCFullYear() + 100);
        break;
    case SimileAjax.DateTime.MILLENNIUM:
        date2.setUTCFullYear(date2.getUTCFullYear() + 1000);
        break;
    }

    date.setTime(date2.getTime() - timeShift);
};

/**
 * Returns a new date object with the given time offset removed.
 *
 * @param {Date} date the starting date
 * @param {Number} timeZone a timezone specified in an hour offset to remove
 * @return {Date} a new date object with the offset removed
 */
SimileAjax.DateTime.removeTimeZoneOffset = function(date, timeZone) {
    return new Date(date.getTime() + 
        timeZone * SimileAjax.DateTime.gregorianUnitLengths[SimileAjax.DateTime.HOUR]);
};

/**
 * Returns the timezone of the user's browser.
 *
 * @return {Number} the timezone in the user's locale in hours
 */
SimileAjax.DateTime.getTimezone = function() {
    var d = new Date().getTimezoneOffset();
    return d / -60;
};