demo validation

index.js

@@ -1,11 +1,12 @@
 const express = require('express')
 var path = require('path');
+const { TreeNode, preorderTraversal } = require('./preorderTraversal')
 
 const PORT = process.env.PORT || 3000
 const HOST = '0.0.0.0'
 
 // !* Edit here for demos
-const RELEASE_NO = 'PROD-136'
+const RELEASE_NO = 'PROD-173'
 
 const api = express()
 
@@ -15,8 +16,23 @@ api.set('view engine', 'pug');
 api.use(express.static(path.join(__dirname, 'public')));
 
 api.get('/', (req, res) => {
+  // Create a binary tree
+  //     1
+  //    / \
+  //   2   3
+  //  / \
+  // 4   5
+  let 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);
+
+  // Call preorderTraversal with the root node
+  let result = preorderTraversal(root);
   res.render('index', {
-    release_no: RELEASE_NO
+    release_no: RELEASE_NO,
+    orderedNodes: result
   })
 })
 

preorderTraversal.js

@@ -0,0 +1,19 @@
+function TreeNode(val) {
+    this.val = val;
+    this.left = this.right = null;
+}
+
+function preorderTraversal(root) {
+    let result = [];
+    if (root !== null) {
+        result.push(root.val);
+        preorderTraversal(root.left);
+        preorderTraversal(root.right);
+    }
+    return result;
+}
+
+module.exports = {
+    TreeNode,
+    preorderTraversal
+}

preorderTraversal.test.js

@@ -0,0 +1,16 @@
+// This test checks if the preorderTraversal orders as expected
+
+const { TreeNode, preorderTraversal } = require('./preorderTraversal');
+
+test('should properly traver and order the binary tree nodes', async () => {
+    // Arrange
+    let 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);
+    // Act
+    let result = preorderTraversal(root);
+    // Assert
+    expect(result).toStrictEqual([1, 2, 4, 5, 3])
+});

views/index.pug

@@ -15,4 +15,5 @@ html(lang="en")
       h1 Success!
       h2 #{release_no}
       p Congratulations, your service was deployed successfully on the Developer Control Plane!
+      p The order of traversal of nodes is #{orderedNodes.join(" -> ")}
       a(href="https://cto.ai/docs") Explore our Documentation