Node.js res.send is not a function

Question

I'm trying the following code but it's giving me an error, "res.send is not a function". Please help me.

Here's the code:

var http = require('http');
var fs = require('fs');
var connect = require('connect');
var express = require('express');

var app = express();
app.get('/', function(res, req  ) {
        res.send('Hello World');
    });

var server = app.listen(8888, function(){
    var host = server.address().address;
    var port = server.address().port;
    console.log("Example app listening at http://%s:%s", host, port);
});

The server is running fine and is connecting. The complete error that is being displayed is something like this:

TypeError: res.send is not a function at c:\wamp\www\node\server.js:8:13 at Layer.handle [as handle_request] (c:\wamp\www\node\node_modules\express\lib\router\layer.js:95:5) at next (c:\wamp\www\node\node_modules\express\lib\router\route.js:137:13) at Route.dispatch (c:\wamp\www\node\node_modules\express\lib\router\route.js:112:3) at Layer.handle [as handle_request] (c:\wamp\www\node\node_modules\express\lib\router\layer.js:95:5) at c:\wamp\www\node\node_modules\express\lib\router\index.js:281:22 at Function.process_params (c:\wamp\www\node\node_modules\express\lib\router\index.js:335:12) at next (c:\wamp\www\node\node_modules\express\lib\router\index.js:275:10) at expressInit (c:\wamp\www\node\node_modules\express\lib\middleware\init.js:40:5) at Layer.handle [as handle_request] (c:\wamp\www\node\node_modules\express\lib\router\layer.js:95:5)

Answer 1

According to the API reference , the first param always contain request req , then response res .

So change first param res to req :

app.get('/', function(req, res) {
    res.send("Rendering file")
}

It should fix it.

Answer 2

You've got the res and req parameters the wrong way around.

app.get('/', function(res, req)

should be

app.get('/', function(req, res)

Source: API docs .

Answer 3

交换 req & res : function(req, res)

Answer 4

Everything fine. Good Work. Just make a little change in parameters eg (req, res) instead of (res, req). Its a Rule.

Answer 5

you should use req argument first and res as the second argument this will work without any issue

 app.get('/', function(req, res) { res.send("Rendering file") }

Answer 6

You can change your mind in some cases and could be write like this. note: by default, when you run node server on your local machine. Your host will always be localhost:"your desire port" Thank you!

const express = require("express")
const app = express();
const port = 8888;
// for redering hello you don't need to require fs
const fs = require("fs")

app.get ('/', (req, res) => {
    res.send("hello world")
})


app.listen(port, () => console.log(`Listening on ${port}`))

Answer 7

The middleware function you are writing is a callback function and should follow the order of declaring params function(req, res, next) req for request res for response and next for further operation. You can refer to API reference .

So the proper code would be:

var express = require('express');
var http = require('http');
var fs = require('fs');
var connect = require('connect');

var app = express();
app.get('/', function(req, res) {
        res.send('Hello World');
    });

var server = app.listen(8888, function(){
    var host = server.address().address;
    var port = server.address().port;
    console.log("Example app listening at http://%s:%s", host, port);
});