嗨，请找到答案

const express = require('express');
const app = express();
const port = 8080;

app.get('/', (req, res) => res.send('Hello home!'));
app.get('/about-us', (req, res) => res.send('Hello about us!'));
app.post('/user/set-profile', (req, res) => res.send('Hello profile!'));
//last 404 page 
app.get('*', (req, res) => res.send('Page Not found 404'));
app.listen(port, () => console.log(`Example app listening on port ${port}!`));

虽然上面的答案是正确的，但对于那些希望在IISNODE中工作的人来说，还需要指定

<configuration>
    <system.webServer>
        <httpErrors existingResponse="PassThrough"/>
    </system.webServer>
<configuration>

在你的网里。配置(否则IIS将吃掉您的输出)。

我在定义所有路由后所做的是捕捉潜在的404并转发到错误处理程序，如下所示:

    const httpError = require('http-errors');

    ...

    // API router
    app.use('/api/', routes);
    
    // catch 404 and forward to error handler
    app.use((req, res, next) => {
      const err = new httpError(404)
      return next(err);
    });

    module.exports = app;

你可以把一个中间件放在最后一个位置，它会抛出一个NotFound错误， 甚至直接渲染404页面:

app.use(function(req,res){
    res.status(404).render('404.jade');
});

Express-error-handler允许您为错误指定自定义模板、静态页面或错误处理程序。它还做了其他有用的错误处理，每个应用程序都应该实现，比如防止4xx错误DOS攻击，以及在不可恢复错误时优雅地关闭。以下是你如何做到你所要求的:

var errorHandler = require('express-error-handler'),
  handler = errorHandler({
    static: {
      '404': 'path/to/static/404.html'
    }
  });

// After all your routes...
// Pass a 404 into next(err)
app.use( errorHandler.httpError(404) );

// Handle all unhandled errors:
app.use( handler );

或者对于自定义处理程序:

handler = errorHandler({
  handlers: {
    '404': function err404() {
      // do some custom thing here...
    }
  }
}); 

或者对于自定义视图:

handler = errorHandler({
  views: {
    '404': '404.jade'
  }
});

我发现这个例子很有帮助:

https://github.com/visionmedia/express/blob/master/examples/error-pages/index.js

所以，它实际上是这一部分:

// "app.router" positions our routes
// above the middleware defined below,
// this means that Express will attempt
// to match & call routes _before_ continuing
// on, at which point we assume it's a 404 because
// no route has handled the request.

app.use(app.router);

// Since this is the last non-error-handling
// middleware use()d, we assume 404, as nothing else
// responded.

// $ curl http://localhost:3000/notfound
// $ curl http://localhost:3000/notfound -H "Accept: application/json"
// $ curl http://localhost:3000/notfound -H "Accept: text/plain"

app.use(function(req, res, next) {
  res.status(404);

  // respond with html page
  if (req.accepts('html')) {
    res.render('404', { url: req.url });
    return;
  }

  // respond with json
  if (req.accepts('json')) {
    res.json({ error: 'Not found' });
    return;
  }

  // default to plain-text. send()
  res.type('txt').send('Not found');
});