TypeScript-Backend-Template/src/app.ts

import requestId from 'request-ip';
import express, { Application, NextFunction, Request, Response } from "express";
import config from "./config/config";
import morgan from "./config/morgan";
import path from 'path';
import logger from './config/logger';
import ApiError from './utils/helper/ApiError';
import error from './middleware/error';
import routes from './routes';

class App {
    private app: Application;

    constructor() {
        this.app = express();
        this.initializeMiddlewares();
        this.initializeRoutes();
        this.initializeErrorHandling();
    }

    private initializeMiddlewares(): void {
        if (config.env !== "test") {
            this.app.use(morgan.successHandler);
            this.app.use(morgan.errorHandler);
        }
        this.app.use(requestId.mw());
        this.app.use(express.json());
        this.app.use(express.urlencoded({ extended: true }));
        this.app.use("/public", express.static(path.join(__dirname, "../public")));
    }

    private initializeRoutes(): void {
        this.app.use('/api', routes);
        // Define our routes
        this.app.use((req: Request, res: Response, next: NextFunction) => {
            next(new ApiError(404, "Not found"));
        })
    }

    private initializeErrorHandling(): void {
        this.app.use(error.errorConverter);
        this.app.use(error.errorHandler);
    }

    public listen(port: number): ReturnType<typeof this.app.listen> {
       return this.app.listen(port, () => {
            logger.info(`Server listening on port ${config.port}`);
            logger.info(`Environment :- ${config.env}`);
        })
    }
}

export default new App();