Solution

src/createServer.js

@@ -1,8 +1,78 @@
+/* eslint-disable no-console */
 'use strict';
 
+const http = require('http');
+const fs = require('fs');
+
 function createServer() {
   /* Write your code here */
   // Return instance of http.Server class
+
+  const server = new http.Server();
+
+  server.on('request', (req, res) => {
+    if (req.method === 'POST' && req.url === '/add-expense') {
+      let body = '';
+
+      req.on('data', (chunk) => {
+        body += chunk.toString();
+      });
+
+      req.on('end', () => {
+        let fields;
+
+        try {
+          fields = JSON.parse(body);
+        } catch (err) {
+          res.statusCode = 400;
+
+          return res.end('Invalid JSON');
+        }
+
+        if (!fields.amount || !fields.date || !fields.title) {
+          res.statusCode = 400;
+
+          return res.end('Missing required fields');
+        }
+
+        const filePath = 'db/expense.json';
+
+        const newData = {
+          amount: fields.amount,
+          date: fields.date,
+          title: fields.title,
+        };
+
+        fs.writeFileSync(filePath, JSON.stringify(newData));
+
+        const file = fs.readFileSync(filePath);
+
+        res.setHeader('Content-Type', 'application/json');
+        res.end(file);
+      });
+
+      return;
+    }
+
+    if (req.url !== '/' && req.url !== '/add-expense') {
+      res.statusCode = 404;
+
+      return res.end('Invalid Url');
+    }
+
+    res.setHeader('Content-type', 'text/html');
+
+    res.end(
+      `<form method="POST" action="/add-expense">
+        <input name="date" type="date">
+        <input name="title" type="text">
+        <input name="amount" type="number">
+        <button type="submit">Submit</button>
+      </form>`,
+    );
+  });
+
+  return server;
 }
 
 module.exports = {