我目前正在研究二叉搜索树的 odin 项目。我正在尝试使 deleteNode 工作，并且正在努力删除一个节点（如果它是叶节点）。这是我的代码：class Node { constru...

我目前正在研究二叉搜索树的 odin 项目。我正在尝试使 deleteNode 工作，并且正在努力删除一个节点（如果它是叶节点）。

这是我的代码：

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

class BinarySearchTree {
  constructor() {
    this.root = null;
  }
  buildTree(array) {
    //accepts an array of integers and sort them into binary search tree;
    //loop through the given array, creating a node for each item. insert nodes into the array in a binarySearchTree  manner.
    array.forEach((item) => {
      this.insert(item);
    });
  }
  insert(value) {
    //accepts an integer value and sort it into the tree;
    let newNode = new Node(value);
    if (this.root === null) {
      this.root = newNode;
      return this;
    }
    let current = this.root;
    while (true) {
      if (value === current.value) return undefined;
      if (value < current.value) {
        if (current.left === null) {
          current.left = newNode;
          return this;
        }
        current = current.left;
      } else if (value > current.value) {
        if (current.right === null) {
          current.right = newNode;
          return this;
        }
        current = current.right;
      }
    }
  }

 deleteNode(value) {
    let current = this.root;
    let prev;
    if (!current) {
      console.log("hello");
      return undefined;
    }
    while (current) {
      if (current.value > value) {
        prev = current;
        current = current.left;
      } else if (current.value < value) {
        prev = current;
        current = current.right;
      } else {
        //node found.
        //case 1: node is leaf node, no left and right children
        if (!current.left && !current.right) {
          if (prev.value > current.value) {
            prev.left = null;
          } else {
            prev.right = null;
          }

          console.log("leaf node deleted", current);
          return this;
        }
        //case 2: node has either left or right child
        //case 3: node has both left and right children
      }
    }
  }
  find(value) {
    //accepts an integer value and search for it in the tree. IF found ,return the node with the value;
    if (this.root === null) {
      return undefined;
    }
    let current = this.root;
    while (current) {
      if (current.value === value) {
        return current;
      } else if (current.value > value) {
        current = current.left;
      } else {
        current = current.right;
      }
    }
    return false;
  }

  levelOrder(callback) {
    //BFS
    const queue = [];
    const data = [];
    let node = this.root;
    queue.push(this.root);
    while (queue.length) {
      node = queue.shift();
      data.push(node.value);
      if (node.left) queue.push(node.left);
      if (node.right) queue.push(node.right);
    }
    return data;
  }

  inOrder(callback) {
    //inOrderDFS
    if (this.root === null) {
      return undefined;
    }
    const data = [];
    let current = this.root;
    const traverse = (node) => {
      if (node.left) {
        traverse(node.left);
      }
      data.push(node.value);
      if (node.right) {
        traverse(node.right);
      }
    };
    traverse(current);
    return data;
  }
  preOrder(callback) {
    //preOrderDFS
    if (this.root === null) {
      return undefined;
    }
    const data = [];
    let current = this.root;
    const traverse = (node) => {
      data.push(node.value);
      if (node.left) traverse(node.left);
      if (node.right) traverse(node.right);
    };
    traverse(current);
    return data;
  }

  postOrder(callback) {
    //postOrderDFS
    if (this.root === null) {
      return undefined;
    }
    const data = [];
    let current = this.root;
    const traverse = (node) => {
      if (node.left) traverse(node.left);
      if (node.right) traverse(node.right);
      data.push(node.value);
    };
    traverse(current);
    return data;
  }
}

const odinTree = new BinarySearchTree();
const array = [10, 20, 12, 15, 11, 50, 35, 21, 5, 2, 9, 3];
odinTree.buildTree(array);

以下是 deleteNode 的代码：

 deleteNode(value) {
    let current = this.root;
    let prev;
    if (!current) {
      console.log("hello");
      return undefined;
    }
    while (current) {
      if (current.value > value) {
        prev = current;
        current = current.left;
      } else if (current.value < value) {
        prev = current;
        current = current.right;
      } else {
        //node found.
        //case 1: node is leaf node, no left and right children
        if (!current.left && !current.right) {
          if (prev.value > current.value) {
            prev.left = null;
          } else {
            prev.right = null;
          }

          console.log("leaf node deleted", current);
          return this;
        }
        //case 2: node has either left or right child
        //case 3: node has both left and right children
      }
    }
  }

我尝试在控制台上运行代码，它确实有效。但是，我尝试刷新页面并按下键盘上的 up 键来运行相同的代码以删除相同的叶节点，结果卡住了。

我很确定我的代码没问题，因为我尝试在几个叶节点上输入 tree.deleteNode，它们都成功了。只有当我尝试按 keyup 运行 deleteNode 时，页面才会卡住。

任何意见都将受到赞赏，谢谢！