Air 空中数据处理

我有：

我想在覆盖targetFile之前备份它

也许是有日期戳的东西，这样我就有了无限的备份，当然会定期清除（读：每一次蓝月一次）

然后

(function() {
    Date.prototype.toYMD = Date_toYMD;
    function Date_toYMD() {
        var year, month, day;
        year = String(this.getFullYear());
        month = String(this.getMonth() + 1);
        if (month.length == 1) {
            month = "0" + month;
        }
        day = String(this.getDate());
        if (day.length == 1) {
            day = "0" + day;
        }
        return '' + year + month + day;
    }
})();

(function() {
    Date.prototype.toHMS = Date_toHMS;
    function Date_toHMS() {
        var hour, minute, second;
        hour = String(this.getHours());
        minute = String(this.getMinutes());
        second = String(this.getSeconds());
        return '' + hour + minute + second;
    }
})();

(function() {
    Date.prototype.toYMD = Date_toYMD;
    function Date_toYMD() {
        var year, month, day;
        year = String(this.getFullYear());
        month = String(this.getMonth() + 1);
        if (month.length == 1) {
            month = "0" + month;
        }
        day = String(this.getDate());
        if (day.length == 1) {
            day = "0" + day;
        }
        return '' + year + month + day;
    }
})();

(function() {
    Date.prototype.toHMS = Date_toHMS;
    function Date_toHMS() {
        var hour, minute, second;
        hour = String(this.getHours());
        minute = String(this.getMinutes());
        second = String(this.getSeconds());
        return '' + hour + minute + second;
    }
})();

var dt = new Date();
var ArcBakFile = air.File.desktopDirectory.resolvePath('myDir/myFile.' + dt.toYMD() + '.' + dt.toHMS() + '.txt');