How can we access variable from callback function in node.js?

Question

var sys = require(\'sys\');
var exec = require(\'child_process\').exec;
var cmd = \'whoami\';
var child = exec( cmd,
      function (error, stdout, stderr) 
      {
         


        

Answer 1

You can write the "exec" statement in a function that has a callback... Like This

var sys = require('sys');
var exec = require('child_process').exec;
var cmd = 'whoami';
function execChild(callback){
    var child = exec( cmd,
          function (error, stdout, stderr) 
          {
            username=stdout.replace('\r\n','');
             callback(username);
          }
 )};
    execChild(function(username){
    console.log(username);
});