nest.object(array) Applies the nest operator to the specified array, returning a nested object. Each entry

set.empty() Returns true if and only if this set has zero values.

map.empty() Returns true if and only if this map has zero entries.

set.each(function) Calls the specified function for each value in this set, passing the value as the first

set.size() Returns the number of values in this set.

d3.keys(object) Returns an array containing the property names of the specified object (an associative array). The order of

d3.set([array[, accessor]]) Constructs a new set. If array is specified, adds the given array of string

map.entries() Returns an array of key-value objects for each entry in this map. The order of the returned entries is arbitrary

d3.map([object[, key]]) Constructs a new map. If object is specified, copies all enumerable properties from

nest.sortKeys(comparator) Sorts key values for the