d3.mouse(container) Returns the x and y coordinates of the current event relative to the specified container. The container may be an HTML or SVG container element, such as a G element or an SVG element. The coordinates are returned as a two-element array of numbers [x, y].

link.links([links]) If links is specified, sets the array of links associated with this force, recomputes the distance and strength parameters for each link, and returns this force. If links is not specified, returns the current array of links, which defaults to the empty array. Each link is an object with the following properties: source - the link’s source node; see simulation.nodes target - the link’s target node; see simulation.nodes index - the zero-based index into links, assigned

local.get(node) Returns the value of this local on the specified node. If the node does not define this local, returns the value from the nearest ancestor that defines it. Returns undefined if no ancestor defines this local.

quantile.invertExtent(value) Returns the extent of values in the domain [x0, x1] for the corresponding value in the range: the inverse of quantile. This method is useful for interaction, say to determine the value in the domain that corresponds to the pixel location under the mouse.

d3.schemeCategory20c An array of twenty categorical colors represented as RGB hexadecimal strings. This color scale includes color specifications and designs developed by Cynthia Brewer (colorbrewer2.org).

d3.curveBasisClosed(context) Produces a closed cubic basis spline using the specified control points. When a line segment ends, the first three control points are repeated, producing a closed loop with C2 continuity.

d3.brush() Creates a new two-dimensional brush.

set.each(function) Calls the specified function for each value in this set, passing the value as the first two arguments (for symmetry with map.each), followed by the set itself. Returns undefined. The iteration order is arbitrary.

transition.style(name, value[, priority]) For each selected element, assigns the style tween for the style with the specified name to the specified target value with the specified priority. The starting value of the tween is the style’s computed value when the transition starts. The target value may be specified either as a constant or a function. If a function, it is immediately evaluated for each selected element, in order, being passed the current datum d and index i, with the this contex

d3.selector(selector) Given the specified selector, returns a function which returns the first descendant of this element that matches the specified selector. This method is used internally by selection.select. For example, this: var div = selection.select("div"); Is equivalent to: var div = selection.select(d3.selector("div"));