d3.quadtree()

d3.quadtree([data[, x, y]])

Creates a new, empty quadtree with an empty extent and the default x- and y-accessors. If data is specified, adds the specified array of data to the quadtree. This is equivalent to:

var tree = d3.quadtree()
    .addAll(data);

If x and y are also specified, sets the x- and y- accessors to the specified functions before adding the specified array of data to the quadtree, equivalent to:

var tree = d3.quadtree()
    .x(x)
    .y(y)
    .addAll(data);