How to JSON Stringify a JavaScript Date and Preserve Timezone

How to JSON stringify a javascript Date and preserve timezone

Assuming you have some kind of object that contains a Date:

var o = { d : new Date() };

You can override the toJSON function of the Date prototype. Here I use moment.js to create a moment object from the date, then use moment's format function without parameters, which emits the ISO8601 extended format including the offset.

Date.prototype.toJSON = function(){ return moment(this).format(); }

Now when you serialize the object, it will use the date format you asked for:

var json = JSON.stringify(o);  //  '{"d":"2015-06-28T13:51:13-07:00"}'

Of course, that will affect all Date objects. If you want to change the behavior of only the specific date object, you can override just that particular object's toJSON function, like this:

o.d.toJSON = function(){ return moment(this).format(); }

JSON Stringify changes time of date because of UTC

Recently I have run into the same issue. And it was resolved using the following code:

x = new Date();
let hoursDiff = x.getHours() - x.getTimezoneOffset() / 60;
let minutesDiff = (x.getHours() - x.getTimezoneOffset()) % 60;
x.setHours(hoursDiff);
x.setMinutes(minutesDiff);

Json Stringify date produces a wrong date compared to javascript date

This is due to the timezone component in the Date. The work around I did was:

var date = $(.datepicker).datepicker('getDate');
var utcDate = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate(), date.getHours(), date.getMinutes()))
var result = Json.stringify(utcDate);

The removes the timezone component.

Why does JSON.stringify screw up my datetime object?

There is not special way to serialize Date objects in JSON. That's why you get the standardized string representation. You need to convert them back to Date objects by passing them to the Date constructor.

item['created_at'] = new Date(item['created_at']);

Update: With the reviver function (see comments), you can get the Date objects back.

var item = JSON.parse(row, function (key, value) {
  if (key === 'created_at') {
    return new Date(value);
  } else {
    return value;
  }
});

Issues with Date() when using JSON.stringify() and JSON.parse()

If you look at the output of JSON.stringify for a Date, you'll see that:

JSON.stringify(new Date())

Results in a string. JSON does not have a primitive representation of Date objects that JSON.parse will turn back into a Date object automatically.

The Date object's constructor can take a date string, so you can turn those string values back into dates by doing:

var x = new Date(JSON.parse(JSON.stringify(new Date())));

Then the arithmetic will work.

x = new Date(JSON.parse(JSON.stringify(new Date())))
y = new Date(JSON.parse(JSON.stringify(new Date())))
y - x
=> 982

JSON date, display original date in the server's timezone

Just use the parseZone function, like so:

moment.parseZone(s)

Documentation is here.

Alternatively, you can use the older approach, which does the same thing:

moment(s).zone(s)

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