无法修改JavaScript中的二叉树节点

class TreeNode {
  constructor(value) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}

function modifyTreeNode(root, targetValue, newValue) {
  if (root === null) {
    return;
  }
  
  if (root.value === targetValue) {
    root.value = newValue;
  }
  
  modifyTreeNode(root.left, targetValue, newValue);
  modifyTreeNode(root.right, targetValue, newValue);
}

// 创建一个二叉树
const root = new TreeNode(1);
root.left = new TreeNode(2);
root.right = new TreeNode(3);
root.left.left = new TreeNode(4);
root.left.right = new TreeNode(5);

// 修改节点值
modifyTreeNode(root, 4, 10);

console.log(root.left.left.value); // 输出 10