date formatting with/without Moment.js

Question

I am trying to reformat a date that I am getting from an API. In the object I have:

created_at: "2013-06-13T16:29:55.245Z"

I would like to display the date as 6/13/2013. Someone suggested I use moment.js. It has tons of documentation but i'm a bit confused on how to use it. can someone please help or suggest an easier way to do this?

Answer 1

No need to modify the original string, you can just use it like this:

alert(moment("2013-06-13T16:29:55.245Z").format("M/DD/YYYY"));

Works well: http://jsfiddle.net/K5ub8/2/

Answer 2

In moments you can just do this

var timeStr = "2013-06-13T16:29:55.245Z",
    newFormat = moment(timeStr).format('M/DD/YYYY');

document.body.textContent = newFormat;

<script src="https://rawgithub.com/timrwood/moment/2.9.0/min/moment.min.js"></script>

Output

6/13/2013 

Without moments and using pure string manipulation rather than a new Date object, you could do

var timeStr = "2013-06-13T16:29:55.245Z",
    temp = timeStr.split("T")[0].split("-").reverse(),
    newFormat;

temp[0] = temp.splice(1, 1, temp[0])[0];
newFormat = temp.join("/");
if (newFormat.charAt(0) === "0") {
  newFormat = newFormat.slice(1);
}

document.body.textContent = newFormat;

Output

6/13/2013 

By using the Date object see @Antony answer. Answer removed

Or if you need it to be more cross-browser compatible with the Date object but still string parsing.

var timeStr = "2013-06-13T16:29:55.245Z",
    intermediate = timeStr.split("T"),
    newStr = intermediate[0].split("-").join("/") + " " + intermediate[1].split(".")[0] + " GMT",
    newDate = new Date(newStr),
    newFormat = (1 + newDate.getUTCMonth()) + "/" + newDate.getUTCDate() + "/" + newDate.getFullYear();

document.body.textContent = newFormat;

Output

6/13/2013 

Finally, you can split the string into component parts and feed it into Date.UTC using these arguments, rather than let Date do the string parsing.

Date.UTC(year, month, day [, hour, minute, second, millisecond]);

So perhaps you can now see why people suggest using moments.js, but so long as you have the knowledge then it is not too painful to do it yourself without a library.