路由时 express.js 不显示 console.log 消息

Question

Note: I am very new to express

var express = require('express');
var app = express();

app.get('/', function(req, res) {
   res.send('id: ' + req.params.id + ' and name: ' + req.params.name);
});
var things = require('./things/things.js');

//both index.js and things.js should be in same directory
app.use('/things', things);
//Simple request time logger
app.use('/',function(req, res, next){
   console.log("A new request received at " + Date.now());

   //This function call is very important. It tells that more processing is
   //required for the current request and is in the next middleware
   //function/route handler.
   next();
});

app.listen(3000);

I am learning about middleware functions and am trying to show a console.log message when I go to localhost:3000, but nothing shows up in my console, what am I missing here?

Answer 1

The problem is that Express passes requests to both middleware and route handlers in order of their declaration. If any of them are able to handle the request (by sending back a response), any other matching middleware or route handlers that got declared later won't get called.

That's what's happening in your situation, where your middleware is declared after the route handlers.

Try moving your middleware to the front:

app.use('/',function(req, res, next){
   console.log("A new request received at " + Date.now());
   next();
});

app.get('/', function(req, res) {
   res.send('id: ' + req.params.id + ' and name: ' + req.params.name);
});

var things = require('./things/things.js');

app.use('/things', things);

Answer 2

First, you need to check the file structure. If index.js and things.js are in the same directory then you need to change the require function to var things = require('./things.js');

Next, verify that you are looking in the correct place, the console.log() message will appear in the terminal window where you loaded the express server, not in the console in your web browser.

Answer 3

The correct 'id' and 'name' of the parameters in get is like this

app.get('/:id/:name', function(req, res) {
   res.send('id: ' + req.params.id + ' and name: ' + req.params.name);
});

Answer 4

The console module provides a simple debugging console that is similar to the JavaScript console mechanism provided by web browsers. https://nodejs.org/api/console.html

Node Server generated console.log message in our terminal logs (Not on the browser).

https://expressjs.com/en/starter/hello-world.html

Related: https://www.twilio.com/blog/guide-node-js-logging