nest.key(key) Registers a new key function. The key function will be invoked for each element in the

map.has(key) Returns true if and only if this map has an entry for the specified key string. Note: the value

d3.entries(object) Returns an array containing the property keys and values of the specified object (an associative array).

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

nest.sortKeys(comparator) Sorts key values for the

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

map.get(key) Returns the value for the specified key string. If the map does not have an entry for the specified

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

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

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