The TreeWalker.previousSibling() method moves the current Node to its previous sibling, if any, and returns the found sibling. If there is no such node, it returns null and the current node is not changed.
previousSibling()None.
A Node object or null.
const treeWalker = document.createTreeWalker(
document.body,
NodeFilter.SHOW_ELEMENT,
{
acceptNode(node) {
return NodeFilter.FILTER_ACCEPT;
},
},
false,
);
const node = treeWalker.previousSibling(); // returns null as there is no previous siblingTreeWalker interface it belongs to.