[feature] Global customise-able d3 locale

Feature description

The default locale (notably for currency values) is US English. For other countries where currency might be in Euros or Pounds (or who might want to use commas or stops differently), this makes number formatting hard.

To do this we would need to set a locale for d3 before we call d3.format() on anything as per the docs: https://github.com/d3/d3-3.x-api-reference/blob/master/Localization.md

I think this should be an option in superset_config.py so that it can be optionally set for any given deployment.

As a bonus point, I think it could be neat to override locales for given metrics. This could be powerful for organisations which have data in multiple currencies. For example setting one column in yen, one in euros and one in pounds. If this is easy to implement we could just do this instead of enabling a global override locale.

Potential implementation

For the basic implementation we would need to pass through a json object which was set in a config variable to each visualisation.

in superset_config.py (for UK):

SUPERSET_D3_LOCALE = """
{
  "decimal": ".",
  "thousands": ",",
  "grouping": [3],
  "currency": ["£", ""],
  "dateTime": "%a %e %b %X %Y",
  "date": "%d/%m/%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"]
} """

and then somewhere in the visualisation javascript we would call:

// for d3 v4
 d3.formatDefaultLocale(definition)
// for d4 v3
 d3.locale(definition)

where definition is that JSON object which we defined in superset.py

column level formatting

If we wanted to also allow column level formatting instructions then one option is allowing a JSON payload on the SqlMetric model (and somewhere on the druid metric too?) which was then passed to d3.format() as an override locale.

@mistercrunch @graceguo-supercat @xrmx - does this sound like: a) a good idea for a feature? b) a good idea for implementation? c) what’s the best way to pass through the global locale config to the right javascript? I assume on page load but I don’t know exactly where would make the most sense. Would appreciate some guidance.

Any other feedback welcome - I’m happy to do the legwork to actually implement it because we’ve got enough users that would value it.

[botasky11]

I agree this is a nice feature，recently I encountered this problem。

[PeterCahn]

@tristix I have found a way to change the default locale for the number formatting in the Docker image.

You need to modify the file superset/assets/node_modules/d3-format/src/defaultLocale.js which is there after the command npm ci which installs the node_modules.

At this point I used sed to edit that file, like in these commands:

sed -i 's/\([[:space:]]*\)decimal: "\.",/\1decimal: ",",/g' /home/superset/superset/assets/node_modules/d3-format/src/defaultLocale.js
sed -i 's/\([[:space:]]*\)thousands: ",",/\1thousands: "\.",/g' /home/superset/superset/assets/node_modules/d3-format/src/defaultLocale.js
sed -i 's/\([[:space:]]*\)currency: \["$"\(.*\)/\1currency: \["€"\2/g'  /home/superset/superset/assets/node_modules/d3-format/src/defaultLocale.js

In this way the npm run build apply the modifications in the javascripts used by Superset.

I am able also to change the file defaultLocal.js at runtime when the image is running in development mode, with the folder superset mounted and accessible from inside the container.

I am afraid that even if you are not using Docker, the only way is to rebuild everything.

Hope this help, waiting for the new feature.