javascript - Able to create user without providing security credentials -

i trying create new iam user in account.as can see in code, have not provided kinds of security credentials in code still new user created in account. how code able link account without credentials?. have no credentials file stored anywhere on computer.

var aws = require('aws-sdk');  // create iam service object var iam = new aws.iam({apiversion: '2010-05-08'}); var username= process.argv[2];  var params = {    username: username };  iam.getuser(params, function(err, data) {    if (err && err.code === 'nosuchentity') {      iam.createuser(params, function(err, data) {       if (err) {          throw err;       } else {          console.log("success", data);       }     });   } else {         console.log("user " + process.argv[2] + " exists",          data.user.userid);     } });