stratify.parentId([parentId]) If parentId is specified, sets the parent id accessor to the given function and returns this stratify operator. Otherwise, returns the current parent id accessor, which defaults to: function parentId(d) { return d.parentId; } The parent id accessor is invoked for each element in the input data passed to the stratify operator, being passed the current datum (d) and the current index (i). The returned string is then used to identify the node’s relationships in c

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

d3.text(url[, callback]) Creates a request for the text file at the specified url with the default mime type text/plain. This convenience constructor is approximately equivalent to: d3.request(url) .mimeType("text/plain") .response(function(xhr) { return xhr.responseText; }) .get(callback);

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

point.step() Returns the distance between the starts of adjacent points.

graticule.stepMajor([step]) If step is specified, sets the major step for this graticule. If step is not specified, returns the current major step, which defaults to ⟨90°, 360°⟩.

axis.tickSizeOuter([size]) If size is specified, sets the outer tick size to the specified value and returns the axis. If size is not specified, returns the current outer tick size, which defaults to 6. The outer tick size controls the length of the square ends of the domain path, offset from the native position of the axis. Thus, the “outer ticks” are not actually ticks but part of the domain path, and their position is determined by the associated scale’s domain extent. Thus, outer ticks m

map.each(function) Calls the specified function for each entry in this map, passing the entry’s value and key as arguments, followed by the map itself. Returns undefined. The iteration order is arbitrary.

nest.map(array) Applies the nest operator to the specified array, returning a nested map. Each entry in the returned map corresponds to a distinct key value returned by the first key function. The entry value depends on the number of registered key functions: if there is an additional key, the value is another map; otherwise, the value is the array of elements filtered from the input array that have the given key value. If no keys are defined, returns the input array.

pow.ticks([count]) See continuous.ticks.