Res.Render is not a function error in node.js

问题

I am getting an "res.render is not a function error" in the Windows 10 Command Prompt when I try to run my node.js code.

What is causing this error and how can I get rid of it?

Here is my .js file:

/*eslint-env node*/

//------------------------------------------------------------------------------
// node.js starter application for Bluemix
//------------------------------------------------------------------------------

// HTTP request - duas alternativas
var http = require('http');
var request = require('request');

// cfenv provides access to your Cloud Foundry environment
// for more info, see: https://www.npmjs.com/package/cfenv
var cfenv = require('cfenv');

//chama o express, que abre o servidor
var express = require('express');

// create a new express server 
var app = express();

// serve the files out of ./public as our main files
app.use(express.static(__dirname + '/public'));

// get the app environment from Cloud Foundry
var appEnv = cfenv.getAppEnv();

// start server on the specified port and binding host
app.listen(appEnv.port, '0.0.0.0', function() {
    // print a message when the server starts listening
    console.log("server starting on " + appEnv.url);
});


app.get('/home1', function(res){
    http.get('http://developers.agenciaideias.com.br/cotacoes/json', function(res){
		var body = '';
		res.on('data', function(chunk){
			body += chunk;
		});
		res.on('end', function(){
			var json = JSON.parse(body);
			var cotacao = json["bovespa"]["cotacao"];
			var CotacaoDolar= json["dolar"]["cotacao"];
			var VariacaoDolar=json["dolar"]["variacao"];
			var CotacaoEuro=json["euro"]["cotacao"];
			var VariacaoEuro=json["euro"]["variacao"];
			var Atualizacao=json["atualizacao"];
			
		
		res.render('cotacao.jade',{title:'Hey', message:'Sua cotação foi de'});
	
		
		});
	});
});

Error:

回答1:

I don't see where jade is hooked into your Express app. In order for res.render() to know about jade templates, you have to hook a jade handler into Express.

If jade is installed properly, you should be able to do this to hook it into Express:

app.set('view engine', 'jade');

Express doc for this.

---

In addition, you have named two arguments in the same scope as res. Change the name of the second one that is part of the http.get() so you can still access the higher scoped one that is the actual Express response object.

app.get('/home1', function (res) {
    http.get('http://developers.agenciaideias.com.br/cotacoes/json', function (res2) {
        var body = '';
        res2.on('data', function (chunk) {
            body += chunk;
        });
        res2.on('end', function () {
            var json = JSON.parse(body);
            var cotacao = json["bovespa"]["cotacao"];
            var CotacaoDolar = json["dolar"]["cotacao"];
            var VariacaoDolar = json["dolar"]["variacao"];
            var CotacaoEuro = json["euro"]["cotacao"];
            var VariacaoEuro = json["euro"]["variacao"];
            var Atualizacao = json["atualizacao"];
            res.render('cotacao.jade', {
                title: 'Hey',
                message: 'Sua cotação foi de'
            });
        });
    });
});

回答2:

You're dealing with two sets of HTTP requests/responses.

One you are receiving:

app.get('/home1', function(res){

and one you are making:

http.get('http://developers.agenciaideias.com.br/cotacoes/json', function(res){

… but you've given them both the same variable name (res) so one masks the other and prevents you from accessing it.

Change the name of one of them.

来源：https://stackoverflow.com/questions/34109203/res-render-is-not-a-function-error-in-node-js