I have a date value 2016-02-18 and I want to convert it to Feb 18.

I tried the following code, but it returns an error that get.month is not a function. I have also tried using format.parse(), but that didn't work either.

My code :

var dateLast = "2016-02-18";
var date = Date.parse(dateLast.replace(/-/g,"/"));
var format =  d3.time.format("%b-%d");
var dateConvert = format(date);
console.log(dateConvert);

The error message :

TypeError: d.getMonth is not a function at d3_time_formats.b (d3.js:2517) at format (d3.js:2431)

I have a date value 2016-02-18 and I want to convert it to Feb 18.

I tried the following code, but it returns an error that get.month is not a function. I have also tried using format.parse(), but that didn't work either.

My code :

var dateLast = "2016-02-18";
var date = Date.parse(dateLast.replace(/-/g,"/"));
var format =  d3.time.format("%b-%d");
var dateConvert = format(date);
console.log(dateConvert);

The error message :

TypeError: d.getMonth is not a function at d3_time_formats.b (d3.js:2517) at format (d3.js:2431)

• javascript
• date
• d3.js
• date-format
• time-format

Share Improve this question Follow edited May 10, 2018 at 16:57 John Slegers 47.2k2323 gold badges204204 silver badges173173 bronze badges asked Feb 24, 2016 at 12:30 ImoImo 1,47544 gold badges3030 silver badges5757 bronze badges 1

• which version of d3 are you using, and on which browser does the error happen? – Mehdi Commented Feb 24, 2016 at 12:35

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2 Answers 2

Sorted by: Reset to default 4

You need to pass Date object into format function (see documentation):

var dateLast = "2016-02-18";
var date = Date.parse(dateLast.replace(/-/g,"/"))
var format = d3.time.format("%b-%d");
var dateConvert = format(new Date(date))
console.log(dateConvert)

The D3.js way :

Using d3.time.format, the most efficient way to achieve what you're going for, is this :

var dateLast = "2016-02-18";
var format = d3.time.format("%b %d");
var dateConvert = format(new Date(dateLast));

alert(dateConvert); // Output : Feb 18

(See also this Fiddle)

So, basically, you don't need this dateLast.replace or Date.parse at all. You can just use your date string directly as input of new Date().

---

The vanilla JS way :

Personally, I wouldn't even use d3 (or any other library) at all to format dates. You can do it in vanilla JS with about the same amount of code :

var dateLast = "2016-02-18";
var format = { month : 'short', day : 'numeric' };
var dateConvert = new Date(dateLast).toLocaleDateString('en-US', format);

alert(dateConvert); // Output : Feb 18

(See also this Fiddle).