d3.bin with date/time values

[Fil]

This is a bit of an open question rather than a specific issue, but, wouldn't it be useful to have a specific mode for dates?

Currently, to get meaningful bins of datetime data points, I believe one has to compute the thresholds outside, and do something like e.g.:

const ticks = d3.scaleTime().domain(d3.extent(data, d => d.date)).ticks(20);
bins = d3.bin().thresholds(ticks)(data)

and then, convert each bin’s x0 and x1 to Date objects.

See https://observablehq.com/d/8ab770342a94e839 for an example.

(maybe linked to #77)

[Fil]

The solution may be as simple as introducing

d3.thresholdsTime = n => (data, min, max) => d3.scaleTime().domain([min, max]).ticks(n)

which would be called like this:

d3.bin().value(d => d.date)
  .thresholds(d3.thresholdsTime(20))   (data)

where n = 20 is a hint of the number of bins we're looking for.

[Fil]

It's difficult to introduce this in d3-array (depends on d3-scale), so I guess it's better to leave it as a suggestion in the documentation. To start, an example notebook, which could be linked from README.