This method returns the array of data for the first group in the selection. Note
that the data method cannot be used to clear data bindings, since it computes a
data join; use datum(null) to clear bound data.
This may seem a bit improbable at first, but I ran into this when
testing something unrelated in Firefox, which turns out to have:
"watch" in {} === true
Rather than producing separate files for each module, the default build now
produces a single file. This should encourage better page-load performance as
the files were relatively small. Also, it's easier to deal with only one file
rather than many, especially if you're not quite sure what the dependencies are.
You may still create minimized builds, if you don't want every feature.
This commit also demotes the chart components to the examples directory, rather
than keeping them as part of the core library. As always, D3 is not a charting
library, and these were ever only intended to serve as examples.
Due to the ordering in which the prototypes are defined, it was still undefined!
Also, the empty method depends on the node method being defined. Added a test.
Mike Bostock
Jason Davies