As I delved into the world of TypeScript and Node, I stumbled upon a perplexing line of code:
public app: express.Application;
This line is nested within the context of an import statement and a class definition. Let's take a closer look at it:
import express, { Request, Response } from "express";
import bodyParser from "body-parser";
class App {
constructor() {
this.app = express();
this.config();
this.routes();
}
//TODO: What is public app: express.Application
public app: express.Application;
private config(): void {
this.app.use(bodyParser.json());
this.app.use(bodyParser.urlencoded({ extended: false }));
}
private routes(): void {
const router = express.Router();
router.get('/', (req: Request, res: Response) => {
res.status(200).send({
message: 'Hello World!'
})
});
router.post('/', (req: Request, res: Response) => {
const data = req.body;
// query a database and save data
res.status(200).send(data);
});
this.app.use('/', router)
}
}
const app = new App().app;
const port = 4040;
app.listen(port, function() {
console.log('Express server listening on port ' + port);
});
The usage of `public app: express.Application;` has left me puzzled. I am seeking clarity on its purpose and significance in this code snippet. Can someone shed some light on this for me?