Understanding Generator Express

Generator-express is a powerful tool to kickstart your Express.js applications with a robust and well-structured codebase. It helps developers set up their Express projects quickly with a variety of boilerplates and configurations.

Installation

  npm install -g generator-express

Creating a New Express Project

Create a new directory and navigate into it:

  mkdir my-express-app
  cd my-express-app

Now, scaffold a new Express application using generator-express:

  yo express

Useful API Examples

Basic Routing

  app.get('/', (req, res) => {
    res.send('Hello World!');
  });

Route Parameters

  app.get('/users/:userId', (req, res) => {
    const userId = req.params.userId;
    res.send(`User ID: ${userId}`);
  });

Middleware Usage

  const myLogger = (req, res, next) => {
    console.log('Logged');
    next();
  };
  app.use(myLogger);

Serving Static Files

  app.use(express.static('public'));

Handling Errors

  app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).send('Something broke!');
  });

Working with JSON

  app.use(express.json());
  app.post('/users', (req, res) => {
    const newUser = req.body;
    res.send(`User ${newUser.name} added!`);
  });

Complete Application Example

Here is an example of a complete Express application using the APIs mentioned above:

  const express = require('express');
  const app = express();
  const port = 3000;

  app.use(express.json());

  const myLogger = (req, res, next) => {
    console.log('Logged');
    next();
  };
  app.use(myLogger);

  app.get('/', (req, res) => {
    res.send('Hello World!');
  });

  app.get('/users/:userId', (req, res) => {
    const userId = req.params.userId;
    res.send(`User ID: ${userId}`);
  });

  app.post('/users', (req, res) => {
    const newUser = req.body;
    res.send(`User ${newUser.name} added!`);
  });

  app.use(express.static('public'));

  app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).send('Something broke!');
  });

  app.listen(port, () => {
    console.log(`Example app listening at http://localhost:${port}`);
  });

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