res.write is not returning the expected value

Question

This is the code:

var http = require('http')

var options = { 
    hostname: 'localhost',
    method: 'POST',
    port: 8000,
    path: '/'
}

var s = 3;

http.request(options, (res)=>{  
}).end(s+'')


http.createServer((req, res)=>{ 
    res.writeHead(200, {'Content-type': 'text/plain'})
    var a = "";
    req.on('data', (data)=>{        
        a+= data
    })  
    req.on('end', ()=>{
        res.write(a)
        res.end()       
    })  
}).listen(8000)

Why might the server be returning invalid information to the client when a return value of 3 is expected?

Answer 1

I solved it. It was a problem of visibility of variable a.

var http = require('http')
var a = '';
var options = { 
    hostname: 'localhost',
    method: 'POST',
    port: 8000,
    path: '/'
}

var s = 3;

http.request(options, (res)=>{  
}).end(s+'')


http.createServer((req, res)=>{ 
    res.writeHead(200, {'Content-type': 'text/plain'})
    req.on('data', (data)=>{        
        a+= data
    })  
    req.on('end', ()=>{
        res.write(a)
        res.end()       
    })  
}).listen(8000)