this behaving unexpectedly in javascript

Asked Nov 05 '19 at 10:39

Active Nov 05 '19 at 10:39

Viewed 32 times

Practicing js on how functions work and how context changes for this keyword when used in different places.

Example below prints a object.

var a = {
        name:"test",
        fn:function(){
           console.log(this); 
        }
a.fn();

But when I run following code this is not

var a = {
        name:"test",
        fn:function(){ 
            var fn1 = function(){
               console.log(this);
            }
           fn1 ();
        }
a.fn();

it prints Global execution context why? Shouldn't it be either printing fn context or a's context?

asked Nov 05 '19 at 10:39

Vinay Prajapati

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1

`this` context in second snippet is related to `fn1` – GrafiCode Nov 05 '19 at 10:41
but it prints global context or window object. – Vinay Prajapati Nov 05 '19 at 10:42
2

You *call* `fn1` as just `fn1()`. That's what makes `this` inside it undefined/`window`. Because there's no `.` before `fn1()`. – deceze Nov 05 '19 at 10:43
@Grafi What does *"related to `fn1`"* mean exactly? – deceze Nov 05 '19 at 10:53
@deceze `this` in second snippet is a reference to `fn1` context, not the container object. Hope this makes sense in english – GrafiCode Nov 05 '19 at 10:55
@Grafi Yeah, no, that's not correct. – deceze Nov 05 '19 at 10:57
@deceze is it because it is not `strict`? https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this#Function_context – GrafiCode Nov 05 '19 at 11:00
@Grafi No, simply because that's not [how `this` works.](https://stackoverflow.com/q/3127429/476) – deceze Nov 05 '19 at 11:07

this behaving unexpectedly in javascript

0 Answers0