Add basic implementation of Express app

Author: arashnrim

app.js

@@ -0,0 +1,14 @@
+const express = require("express");
+const app = express();
+const PORT = 3000;
+
+// Creates a GET endpoint at the root URL that returns a string
+// () => {} is the alternative to function() {}; it's called an arrow function!
+app.get("/", (request, response) => {
+    response.send("Hello, world!");
+});
+
+// Starts the server on port 3000
+app.listen(PORT, () => {
+    console.log(`Server listening on port ${PORT}!`);
+});

package.json

@@ -0,0 +1,6 @@
+{
+    "main": "app.js",
+    "dependencies": {
+        "express": "^4.18.2"
+    }
+}