Binary search tree on JS

JavaScript/4-binarySearchTree.js

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+'use strict';
+
+function Node(parent, data) {
+  this.data = data;
+  this.leftChild = null;
+  this.rightChild = null;
+  this.parent = parent;
+}
+
+Node.prototype.output = function() {
+  if (this.leftChild !== null) {
+    this.leftChild.output();
+  }
+  console.dir(this.data);
+  if (this.rightChild !== null) {
+    this.rightChild.output();
+  }
+};
+
+Node.prototype.search = function(key) {
+  if (this.data === key) return this;
+  if (key < this.data) {
+    if (this.leftChild === null) return null;
+    return this.leftChild.search(key);
+  } else {
+    if (this.rightChild === null) return null;
+    return this.rightChild.search(key);
+  }
+};
+
+
+Node.prototype.insert = function(data) {
+  if (data < this.data) {
+    if (this.leftChild === null) {
+      this.leftChild = new Node(this, data);
+      return;
+    }
+    this.leftChild.insert(data);
+  } else {
+    if (this.rightChild === null) {
+      this.rightChild = new Node(this, data);
+      return;
+    }
+    this.rightChild.insert(data);
+  }
+};
+
+Node.prototype.left = function() {
+  if (this.leftChild !== null) return this.leftChild.left();
+  return this;
+};
+
+function BinarySearchTree() {
+  this.root = null;
+}
+
+BinarySearchTree.prototype.output = function() {
+  if (this.root !== null) {
+    this.root.output();
+  }
+};
+
+BinarySearchTree.prototype.search = function(key) {
+  if (this.root !== null) {
+    return this.root.search(key);
+  }
+  return null;
+};
+
+BinarySearchTree.prototype.min = function() {
+  var current = null;
+  if (this.root !== null) {
+    current = this.root;
+    while (current.leftChild !== null) {
+      current = current.leftChild;
+    }
+    return current;
+  } else return null;
+};
+
+BinarySearchTree.prototype.max = function() {
+  var current = null;
+  if (this.root !== null) {
+    current = this.root;
+    while (current.rightChild !== null) {
+      current = current.rightChild;
+    }
+    return current;
+  } else return null;
+};
+
+BinarySearchTree.prototype.insert = function(data) {
+  if (this.root !== null) {
+    this.root.insert(data);
+  } else this.root = new Node(null, data);
+};
+
+BinarySearchTree.prototype.delete = function(data) {
+  var toDelete = this.root.search(data);
+  if (toDelete === null) return;
+  if (toDelete === this.root) {
+    if (this.root.leftChild === null && this.root.rightChild === null) {
+      this.root = null;
+      return;
+    }
+    if (this.root.leftChild === null) {
+      this.root = this.root.rightChild;
+      return;
+    }
+    if (this.root.rightChild === null) {
+      this.root = this.root.leftChild;
+      return;
+    }
+  } else {
+    if (toDelete.leftChild === null && toDelete.rightChild === null) {
+      if (toDelete.parent.leftChild === toDelete) {
+        toDelete.parent.leftChild = null;
+      } else {
+        toDelete.parent.rightChild = null;
+      }
+      return;
+    }
+    if (toDelete.leftChild === null) {
+      if (toDelete.parent.leftChild === toDelete) {
+        toDelete.parent.leftChild = toDelete.rightChild;
+      } else {
+        toDelete.parent.rightChild = toDelete.rightChild;
+      }
+      return;
+    }
+    if (toDelete.rightChild === null) {
+      if (toDelete.parent.leftChild === toDelete) {
+        toDelete.parent.leftChild = toDelete.leftChild;
+      } else {
+        toDelete.parent.rightChild = toDelete.leftChild;
+      }
+      return;
+    }
+  }
+  var replaceNode = toDelete.rightChild.left();
+  toDelete.data = replaceNode.data;
+  if (replaceNode !== toDelete.rightChild) {
+    if (replaceNode.rightChild === null) {
+      replaceNode.parent.leftChild = null;
+    } else {
+      replaceNode.parent.leftChild = replaceNode.rightChild;
+    }
+  } else if (replaceNode.rightChild === null) {
+    replaceNode.parent.rightChild = null;
+  } else {
+    replaceNode.parent.rightChild = replaceNode.rightChild;
+  }
+};
+
+var tree = new BinarySearchTree();
+tree.insert(15);
+tree.insert(5);
+tree.insert(16);
+tree.insert(3);
+tree.insert(12);
+tree.insert(20);
+tree.insert(10);
+tree.insert(13);
+tree.insert(18);
+tree.insert(23);
+tree.insert(6);
+tree.insert(7);
+tree.output();
+console.log('Min node: ' + tree.min().data);
+console.log('Max node: ' + tree.max().data);
+console.log('Search node 13: ' + tree.search(13) + ': ' + tree.search(13).data);
+console.log('Search node 11: ' + tree.search(11));
+
+//tree.delete(15);
+//console.log('Deleted elem 15!');
+//tree.output();
+
+//tree.delete(13);
+//console.log('Deleted elem 13!');
+//tree.output();
+
+//tree.delete(16);
+//console.log('Deleted elem 16!');
+//tree.output();
+
+tree.delete(5);
+console.log('Deleted elem 5!');
+tree.output();