selectChild method

Selection selectChild([ Union2<bool Function(Element, int, HTMLCollection), String>? selector ])

Returns a new selection with the (first) child of each element of the current selection matching the selector.

d4.selectAll("p".u31).selectChild("b".u22); // the first <b> child of every <p>

If no selector is specified, selects the first child (if any). If the selector is specified as a string, selects the first child that matches (if any). If the selector is a function, it is evaluated for each of the children nodes, in order, being passed the child (child), the child’s index (i), and the list of children (children); the method selects the first child for which the selector return truthy, if any.

Caution

selection.selectChild propagates the parent’s data to the selected child.

Implementation

Selection selectChild(
    [Union2<bool Function(Element, int, HTMLCollection), String>? selector]) {
  return select(
    selector?.split(
          (match) => childFind(match).u21,
          (selector) => childFind(g.childMatcher(selector)).u21,
        ) ??
        childFirst.u21,
  );
}