Function selection_data

external/.d3.js:1905–1942

(value, key)

}

function selection_data(value, key) {
  if (!arguments.length) return Array.from(this, datum);

  var bind = key ? bindKey : bindIndex,
      parents = this._parents,
      groups = this._groups;

  if (typeof value !== "function") value = constant$a(value);

  for (var m = groups.length, update = new Array(m), enter = new Array(m), exit = new Array(m), j = 0; j < m; ++j) {
    var parent = parents[j],
        group = groups[j],
        groupLength = group.length,
        data = arraylike(value.call(parent, parent && parent.__data__, j, parents)),
        dataLength = data.length,
        enterGroup = enter[j] = new Array(dataLength),
        updateGroup = update[j] = new Array(dataLength),
        exitGroup = exit[j] = new Array(groupLength);

    bind(parent, group, enterGroup, updateGroup, exitGroup, data, key);

    // Now connect the enter nodes to their following update node, such that
    // appendChild can insert the materialized enter node before this node,
    // rather than at the end of the parent node.
    for (var i0 = 0, i1 = 0, previous, next; i0 < dataLength; ++i0) {
      if (previous = enterGroup[i0]) {
        if (i0 >= i1) i1 = i0 + 1;
        while (!(next = updateGroup[i1]) && ++i1 < dataLength);
        previous._next = next || null;
      }
    }
  }

  update = new Selection$1(update, parents);
  update._enter = enter;
  update._exit = exit;
  return update;
}

// Given some data, this returns an array-like view of it: an object that
// exposes a length property and allows numeric indexing. Note that unlike