Return removed nodes in BST.

Author: trekhleb

src/data-structures/tree/binary-search-tree/BinarySearchTree.js

@@ -10,9 +10,10 @@ export default class BinarySearchTree{
 
 /**
  * @param{*} value
+ * @return{BinarySearchTreeNode}
  */
 insert(value){
-this.root.insert(value);
+returnthis.root.insert(value);
 }
 
 /**
@@ -25,6 +26,7 @@ export default class BinarySearchTree{
 
 /**
  * @param{*} value
+ * @return{BinarySearchTreeNode}
  */
 remove(value){
 returnthis.root.remove(value);

src/data-structures/tree/binary-search-tree/__test__/BinarySearchTree.test.js

@@ -14,11 +14,13 @@ describe('BinarySearchTree', () =>{
 it('should insert values',()=>{
 constbst=newBinarySearchTree();
 
-bst.insert(10);
-bst.insert(20);
+constinsertedNode1=bst.insert(10);
+constinsertedNode2=bst.insert(20);
 bst.insert(5);
 
 expect(bst.toString()).toBe('5,10,20');
+expect(insertedNode1.value).toBe(10);
+expect(insertedNode2.value).toBe(20);
 });
 
 it('should check if value exists',()=>{
@@ -41,10 +43,13 @@ describe('BinarySearchTree', () =>{
 
 expect(bst.toString()).toBe('5,10,20');
 
-bst.remove(5);
+constremovedNode1=bst.remove(5);
 expect(bst.toString()).toBe('10,20');
-bst.remove(20);
+expect(removedNode1.value).toBe(5);
+
+constremovedNode2=bst.remove(20);
 expect(bst.toString()).toBe('10');
+expect(removedNode2.value).toBe(20);
 });
 
 it('should insert object values',()=>{

src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js

@@ -125,10 +125,13 @@ describe('BinarySearchTreeNode', () =>{
 
 expect(bstRootNode.toString()).toBe('5,10,20');
 
-bstRootNode.remove(5);
+constremovedNode1=bstRootNode.remove(5);
 expect(bstRootNode.toString()).toBe('10,20');
-bstRootNode.remove(20);
+expect(removedNode1.value).toBe(5);
+
+constremovedNode2=bstRootNode.remove(20);
 expect(bstRootNode.toString()).toBe('10');
+expect(removedNode2.value).toBe(20);
 });
 
 it('should remove nodes with one child',()=>{