How to get GET (query string) variables in Express.js on Node.js?

In Express, use req.query.

req.params only gets the route parameters, not the query string parameters. See the express or sails documentation:

(req.params) Checks route params, ex: /user/:id

(req.query) Checks query string params, ex: ?id=12 Checks urlencoded body params

(req.body), ex: id=12 To utilize urlencoded request bodies, req.body should be an object. This can be done by using the _express.bodyParser middleware.

That said, most of the time, you want to get the value of a parameter irrespective of its source. In that case, use req.param('foo'). Note that this has been deprecated as of Express 4: http://expressjs.com/en/4x/api.html#req.param

The value of the parameter will be returned whether the variable was in the route parameters, query string, or the encoded request body.

Side note- if you're aiming to get the intersection of all three types of request parameters (similar to PHP's $_REQUEST), you just need to merge the parameters together-- here's how I set it up in Sails. Keep in mind that the path/route parameters object (req.params) has array properties, so order matters (although this may change in Express 4)

In Express it's already done for you and you can simply use req.query for that:

var id = req.query.id; // $_GET["id"]

Otherwise, in NodeJS, you can access req.url and the builtin url module to url.parse it manually:

var url = require('url');
var url_parts = url.parse(request.url, true);
var query = url_parts.query;

Since you've mentioned Express.js in your tags, here is an Express-specific answer: use req.query. E.g.

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

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

app.listen(3000);

For Express.js you want to do req.params:

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