lib/jsdom/living/helpers/shadow-dom.js
function assignSlotableForTree(root) {
  for (const slot of domSymbolTree.treeIterator(root)) {
    if (isSlot(slot)) {
      assignSlotable(slot);
    }
  }
}
function assignSlotableForTree(root) {
  for (const slot of domSymbolTree.treeIterator(root)) {
    if (isSlot(slot)) {
      assignSlotable(slot);
    }
  }
}
function assignSlotableForTree ( root ) { for ( const slot of domSymbolTree . treeIterator ( root ) ) { if ( isSlot ( slot ) ) { assignSlotable ( slot ) ; } } }
https://dom.spec.whatwg.org/#assign-slotables-for-a-tree
https : // dom . spec . whatwg . org / #assign - slotables - for - a - tree