Option to quote empty strings?

[nrabinowitz]

Right now there's no way to distinguish between empty strings and missing data in formatted output.

csvFormatRows([['value', 'null', 'undefined', 'string'], [0,null,undefined,'']]);

I'd like this to return:

value
0,,,""

But instead I get:

value
0,,,

[mbostock]

This would need a symmetric option with parsing such that an unquoted empty string is mapped to null (or undefined?) whereas a quoted empty string is mapped to the empty string. Specifically in these two places:

d3-dsv/src/dsv.js

Line 105 in 3446779

return text.slice(j, i);

d3-dsv/src/dsv.js

Line 109 in 3446779

return eof = true, text.slice(j, N);