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JavaScript Build a REST API With Express Building API Routes in Express Using Middleware in Express

Posted by Daryl Shy
Daryl Shy
2,536 Points

Why does req.query return undefined?

// Postman----------------------------- // [GET] localhost:3000/color?=green [SEND] //------------------------------------------ var express = require('express');

var app = express(); app.use(function (req, res, next) { console.log("The leaves on the ground are", req.query.color); next(); });

var port = process.env.PORT || 3000;

app.listen(port, function () { console.log(App is running on port ${port}!); });

Jonathan Ankiewicz
Jonathan Ankiewicz
17,901 Points

I believe it should be 

req.params.color

3 Answers

Benjamin Barslev Nielsen
Benjamin Barslev Nielsen
18,958 Points
Benjamin Barslev Nielsen
Benjamin Barslev Nielsen
18,958 Points

The request seems strange:

localhost:3000/color?=green

It should work with this request instead:

localhost:3000?color=green

This should solve the request problem, but you also need to fix the console.log in the last line, since you forget to use "" around the string, so a possible fix could be:

app.listen(port, function () { console.log("App is running on port " + port + "!"); });
J. MORENO
J. MORENO
12,550 Points
J. MORENO
J. MORENO
12,550 Points

The request should have been - http://localhost:3000/?color=green

The ? was misplaced.

J. MORENO
J. MORENO
12,550 Points
J. MORENO
J. MORENO
12,550 Points

after cleaning up the code and using the proper request:

var express = require('express');

var app = express(); var port = process.env.PORT || 3000;

app.use(function (req, res, next) { console.log("The leaves on the ground are", req.query.color); next(); });

app.listen(port, function () { console.log(App is running on port ${port}!); });