select function

Selection select([ Union2<String, Element>? selector ])

Selects the first element that matches the specified selector string.

final svg = d4.select("#chart".u21);

If no elements match the selector, returns an empty selection. If multiple elements match the selector, only the first matching element (in document order) will be selected. For example, to select the first anchor element:

final anchor = d4.select("a".u21);

If the selector is not a string, instead selects the specified node; this is useful if you already have a reference to a node, such as document.body.

d4.select(document.body!.u22).styleSet("background", "red".u22);

Or, to make a clicked paragraph red:

d4.selectAll("p".u31)
    .onBind(
      "click",
      (thisARg, event, d) => d4.select(
        (event.currentTarget as Element).u22,
      ),
    )
    .styleSet("color", "red".u22);

Implementation

Selection select([Union2<String, Element>? selector]) {
  return selector == null
      ? createSelection([
          [null]
        ], root)
      : selector.split(
          (selector) => createSelection([
            [document.querySelector(selector)]
          ], [
            document.documentElement
          ]),
          (node) => createSelection([
            [node]
          ], root),
        );
}