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 (only implement “low” ties strategy #236)
• bin.value? (possibly breaking change, but why would you ever use a constant here?)