Export FormatSpecifier constructor?

[johnmeegan]

Is there any chance of having the ability to format with an object rather than string, e.g.:
format({ precision: 2, type: 'f' })(1.234);

Rather than:
format(".2f")(1.234);

I think it would be nice to allow being that explicit.

I also have a use case for it where I want to convert from other types of format strings into d3-format style. It's easier to convert from "other" to the specifier object, rather than the extra step of making that object a string as well.

I can see it being possible directly in the format function, or if the FormatSpecifier class was exported and had a constructor that accepts either an object or string:
const specifier = new FormatSpecifier({ precision: 2, type: 'f'}).toString();
format(specifier)(1.2345);

[mbostock]

Yeah, I’m in favor of exposing the FormatSpecifier class. 👍