D3.JS: Format as currency euro

Question

The D3 Wiki describes formatting, and how it's possible to format your numbers to dollar values using d3.format("$.,2f");. However, using d3.format("€,.2f"); to format numbers to euro values does not work. What is the appropriate way to do this?

Answer 1

2016-07-06 edit: The answer below was valid for d3 v3. As of d3 v4, d3.formatLocale looks to be the equivalent to what d3.locale was.

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The dollar sign should be kept, as it means "currency".

What you need to do is define the locale (cf. documentation) using d3.locale() function (d3 defaults to en-US).

Here is an example where en-US parameters are kept for all properties, except for the currency, where the $ prefix got replaced by the € suffix ( done with: "currency": ["", "€"]):

var NL = d3.locale ({
  "decimal": ".",
  "thousands": ",",
  "grouping": [3],
  "currency": ["", "€"],
  "dateTime": "%a %b %e %X %Y",
  "date": "%m/%d/%Y",
  "time": "%H:%M:%S",
  "periods": ["AM", "PM"],
  "days": ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
  "shortDays": ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
  "months": ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
  "shortMonths": ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
})

Then you can use NL.numberFormat("$,.2f") to format numbers as Euro.

Working demo.

More information about d3.locale usage in this question.