LeetCode #101 Symmetric Tree with JavaScript

/** * @param {TreeNode} root * @return {boolean} */ const isSymmetric1 = (root) => { const isMirror = (left, right) => { if (!left && !right) return true; if (!left || !right) return false; if (left.val !== right.val) return false; return isMirror(left.left, right.right) && isMirror(left.right, right.left); }; return isMirror(root, root); }; 

/** * @param {TreeNode} root * @return {boolean} */ const isSymmetric2 = (root) => { const queue1 = [root.left]; const queue2 = [root.right]; while (queue1.length > 0 || queue2.length > 0) { const dequeued1 = queue1.shift(); const dequeued2 = queue2.shift(); if (!dequeued1 && !dequeued2) continue; if (!dequeued1 || !dequeued2) return false; if (dequeued1.val !== dequeued2.val) return false; queue1.push(dequeued1.left); queue1.push(dequeued1.right); queue2.push(dequeued2.right); queue2.push(dequeued2.left); } return true; };