Basic structure of the project

- Added a model with in-memory database, and routes, controller and
middleware to enable making initial CRUD calls to endpoints;

- Added jest and an initial test.

src/controllers/topicController.ts

@@ -0,0 +1,79 @@
+import { Request, Response, NextFunction } from 'express';
+import { topics, Topic } from '../models/topic';
+
+// Create a topic
+export const createTopic = (req: Request, res: Response, next: NextFunction) => {
+  try {
+    const { name, content } = req.body;
+    const newTopic: Topic = {
+      id: Date.now(),
+      name,
+      content,
+      createdAt: new Date().toString(),
+      updatedAt: new Date().toString(),
+      version: 1,
+      parentTopicId: 1
+    };
+    topics.push(newTopic);
+    res.status(201).json(newTopic);
+  } catch (error) {
+    next(error);
+  }
+};
+
+// Read all topics
+export const getTopics = (req: Request, res: Response, next: NextFunction) => {
+  try {
+    res.json(topics);
+  } catch (error) {
+    next(error);
+  }
+};
+
+// Read single topic
+export const getTopicById = (req: Request, res: Response, next: NextFunction) => {
+  try {
+    const id = parseInt(req.params.id, 10);
+    const topic = topics.find((i) => i.id === id);
+    if (!topic) {
+      res.status(404).json({ message: 'Topic not found' });
+      return;
+    }
+    res.json(topic);
+  } catch (error) {
+    next(error);
+  }
+};
+
+// Update a topic
+export const updateTopic = (req: Request, res: Response, next: NextFunction) => {
+  try {
+    const id = parseInt(req.params.id, 10);
+    const { name } = req.body;
+    const topicIndex = topics.findIndex((i) => i.id === id);
+    if (topicIndex === -1) {
+      res.status(404).json({ message: 'Topic not found' });
+      return;
+    }
+    topics[topicIndex].name = name;
+    res.json(topics[topicIndex]);
+  } catch (error) {
+    next(error);
+  }
+};
+
+// Delete a topic
+export const deleteTopic = (req: Request, res: Response, next: NextFunction) => {
+  try {
+    const id = parseInt(req.params.id, 10);
+    const topicIndex = topics.findIndex((i) => i.id === id);
+    if (topicIndex === -1) {
+      res.status(404).json({ message: 'Topic not found' });
+      return;
+    }
+    const deletedTopic = topics.splice(topicIndex, 1)[0];
+    res.json(deletedTopic);
+  } catch (error) {
+    next(error);
+  }
+};