String accessors?

[mbostock]

d3-array currently uses function accessors, e.g.

d3.median(data, d => d.foo)

What if a string could be used instead of an accessor for convenience?

d3.median(data, "foo")

There’s some precedent for this, e.g. Lodash’s _.property:

_.map(data, "foo")

(However, I don’t think we want to support nested properties as in Lodash. I think these should be simple property names with no implicit DSL.)

Here’s where it might be used:

• [ ] d3.min
• [ ] d3.minIndex
• [ ] d3.max
• [ ] d3.maxIndex
• [ ] d3.extent
• [ ] d3.sum
• [ ] d3.mean
• [ ] d3.median
• [ ] d3.cumsum
• [ ] d3.quantile
• [ ] d3.quantileSorted
• [ ] d3.variance
• [ ] d3.deviation
• [ ] d3.fsum
• [ ] d3.least
• [ ] d3.leastIndex
• [ ] d3.greatest
• [ ] d3.greatestIndex
• [ ] d3.bisector
• [ ] d3.group
• [ ] d3.groups
• [ ] d3.index
• [ ] d3.indexes
• [ ] d3.rollup
• [ ] d3.rollups
• [ ] d3.groupSort
• [ ] d3.count
• [ ] d3.every
• [ ] d3.some
• [ ] d3.filter
• [ ] d3.map
• [ ] d3.sort
• [ ] d3.rank (#236)
• [ ] bin.value? (possibly breaking change, but why would you ever use a constant here?)