walk.js

function isIgnoredNode(node) {
  if (node.nodeName == 'NOSCRIPT') {
    return true;
  }

  return false;
}

function* nodeIterator(root) {
  const treeWalker = document.createTreeWalker(
    root,
    NodeFilter.SHOW_ALL,
    {
      acceptNode(node) {
        return isIgnoredNode(node)
          ? NodeFilter.FILTER_REJECT
          : NodeFilter.FILTER_ACCEPT;
      },
    }
  );

  let node = treeWalker.currentNode;
  while (node) {
    yield node;
    node = treeWalker.nextNode();
  }
}

export default function* walk(selection) {
  const startContainer = selection.startContainer;
  const startOffset = selection.startOffset;
  const endContainer = selection.endContainer;
  const endOffset = selection.endOffset;

  if (startContainer === endContainer && startOffset == endOffset) {
    return null;
  }

  if (!startContainer.childNodes.length) {
    yield startContainer
  }

  if (startContainer === endContainer) {
    return;
  }

  let ancestor = startContainer;
  while (ancestor) {
    let sibling = ancestor;
    while (sibling.nextSibling) {
      sibling = sibling.nextSibling;
      for (const node of nodeIterator(sibling)) {
        if (!node.childNodes.length) {
          yield node
        }

        if (node === endContainer) {
          return
        }
      }
    }
    ancestor = ancestor.parentNode;
  }
}