Function indexOfNode

packages/@react-spectrum/ai/src/TokenField.tsx:565–573

(node: Node)

});

function indexOfNode(node: Node) {
  let index = 0;
  let n: Node | null = node;

  while ((n = n.previousSibling)) {
    index++;
  }
  return index;
}

export function getSelection(container: Element): [Position, Position] | null {
  let selection = window.getSelection();