<pre class="shiki github-dark shaku"><code>/** * @param {HTMLElement} tree * @return {string[]} *///BFSfunction getTags(tree) { // your code here if(!tree)return []; const res = new Set(); let queue = [tree]; while(queue.length &gt; 0){ let node = queue.pop(); res.add(node.tagName.toLowerCase()); for(const child of node.children){ queue.push(child); } }return [...res];}//DFSfunction getTags(tree,res=new Set()) { if(!tree)return []; res.add(tree.tagName.toLowerCase()); for(const child of tree.children){ getTags(child,res); } return [...res];}</code></pre>

BFS and DFS solution

Given a DOM tree, please return all the tag names it has. Your function should return a unique array of tags names in lowercase, order doesn't matter.…