This Keyword application

#1

function checkingThis(){
let z=10;
console.log(this.z);
}

checkingThis();

OUTPUT
undefined

I am not able to understand why

#2

See this: https://www.w3schools.com/js/js_this.asp

this has different values depending on where it is used:

  • In a method, this refers to the owner object .
  • Alone, this refers to the global object .
  • In a function, this refers to the global object .
  • In a function, in strict mode, this is undefined .
  • In an event, this refers to the element that received the event.
  • Methods like call() , and apply() can refer this to any object .

Since you are writing this.z, it tries to get the value of z defined in global object, which is undefined.

#3

I tried defining z in global object as well,still the output came out to be undefine.

#4

and bhaiya what is strict mode

#5

Send the code you run. I tried it and it’s working.

#6

let z =40; function checkingThis(){ console.log(this.z); } checkingThis();

#7

Anirudh Bhaiya???

#8

With strict mode, you can not, for example, use undeclared variables.

#9

Try var z = 40 instead of let z = 40 This will work.
This is because let , unlike var , does not create a property on the global object. (https://stackoverflow.com/a/11444416/8183406)

#10

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