JavaScript Date / Time

Question

I have the following input and i can change the source of this data

Input

var strDate = "/Date(1391402871117+0100)/";

I can convert it to a date using eval, but i really dont want to eval

var DateResult1 = eval ("new Date(1391402871117+0100)");
console.log(DateResult1); // Date {Mon Feb 03 2014 05:47:51 GMT+0100 (Romance Standard Time)}

I did try this, sadly do not work:

// Remove /Date( )/
strDate = strDate.replace(/[^\d+]/g,'');

var DateResult3 = new Date(strDate);
console.log(DateResult3); //Date {Invalid Date}

When i write result of strDate i manual with out " it work.

var DateResult2 = new Date(1391402871117+0100);
console.log(DateResult2); // Date {Mon Feb 03 2014 05:47:51 GMT+0100 (Romance Standard Time)}

How can convert the input data into a date with out using eval or any library?

Answer 1

You are very likely not getting a correct result out of this code:

var DateResult2 = new Date(1391402871117+0100);

The problem is the addition: 1391402871117+0100 . 0100 is an octal constant, equal to 64 in decimal, which would add 64 milliseconds to the 1391402871117 timestamp. It seems likely to be indended as a time zone instead, but the Date constructor does not support time zones — only UTC and the local time zone of the browser.

Since UNIX timestamps are actually absolute (they are always in UTC), using just the timestamp would result in a Date instance referencing the correct instant in time, but possibly at another time zone. You can disregard the +0100 part, by converting the "1391402871117+0100" into an integer using parseInt :

strDate = strDate.replace(/[^\d+]/g,'');
var DateResult2 = new Date(parseInt(strDate));

Answer 2

If you can change the data source, as you say, why not do this?

Have your data source generate something like this, to add the timezone offset to the timestamp:

// convert timezone offset hours into seconds and add them to the timestamp
return (unixTimestamp + (timezoneOffsetHours * 3600)); 

Then you can do something like this in your JS:

// Math.floor works faster than parseInt to convert a string to integer :)
var timestamp = Math.floor(result of above timestamp generation);
var DateResult = new Date(timestamp);

The reason:

new Date() can't handle timezones specified in this way (or at all as far as I can Google)

Answer 3

try by parsing string to int:

var strDate = "/Date(1391402871117+0100)/";
strDate = strDate.replace(/[^\d+]/g, '');
var DateResult3 = new Date(parseInt(strDate.split('+')[0]) + parseInt(strDate.split('+')[1]));
console.log(DateResult3); 

Here is Demo