Issue with Javascript this context -

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• how access correct `this` inside callback? 5 answers

i'm having issue following code.console.log working fine in logname method not giving desired output in lognameagain method. tried google in vain. please explain going on here?

var testobj = {     name: "this test object",     logname: function() {         console.log(this.name);  //works fine           function lognameagain() {             console.log(this.name); //not giving expected result;         }          lognameagain();      } };  testobj.logname(); 

jsfiddle

seems console.log in lognameagain method pointing window. doesn't make sense me?

update: understand can fixed using bind/call or self don't understand why happening?

try using .bind() (see working jsfiddle):

var testobj = {     name: "this test object",     logname: function() {         console.log(this.name);          var lognameagain = function() {             console.log(this.name);         }.bind(this);          lognameagain();      } };  testobj.logname(); 

the problem new function inside of logname has window (global) context. means need somehow pass in local context. function.prototype.bind that.

if browser support concern, can hacky thing:

var testobj = {     name: "this test object",     logname: function() {         var = this;         console.log(this.name);          var lognameagain = function() {             console.log(that.name);         };          lognameagain();      } };  testobj.logname(); 

that's if need support ie8 , below. here's compat table .bind() (courtesy of mdn: