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JavaScript Getting Started With ES2015 Defining Variables With let and const Using let with for Loops

Aakash Srivastav
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Aakash Srivastav
Full Stack JavaScript Techdegree Student 11,638 Points
Posted by Aakash Srivastav
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Aakash Srivastav
Full Stack JavaScript Techdegree Student 11,638 Points

Using let with for loop

I have a doubt here with const .
If the value of button is changing after every iteration i,e button 0 , button 1 , then why he used const to declare button ?

3 Answers

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

In this video, "button" is assigned inside a loop. Before the loop repeats, "button" is disposed (no longer exists).

On the next iteration, a new "button" is created. The old one is not being re-assigned.

Aakash Srivastav
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.a{fill-rule:evenodd;}techdegree
Aakash Srivastav
Full Stack JavaScript Techdegree Student 11,638 Points
Aakash Srivastav
.a{fill-rule:evenodd;}techdegree
Aakash Srivastav
Full Stack JavaScript Techdegree Student 11,638 Points

In the previous case , the variable status was a part of login_info object.
But here it's a seperate variable.
And if it's the only property of the button that is changing , then how will it be reassigned so that we will get a Uncaugh type error .
Please help me with example.
I am sorry . I am still confused.

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Each iteration has a different context. So this:

for (var i=0; i < 3; i++) {
  const tester = i;
  console.log(tester);
}

Is essentially the same thing as this:

{
  const tester = 0;
  console.log(tester);
}
{
  const tester = 1;
  console.log(tester);
}
{
  const tester = 2;
  console.log(tester);
}

In both cases, the constant(s) exist only between the braces.

Aakash Srivastav
seal-mask
.a{fill-rule:evenodd;}techdegree
Aakash Srivastav
Full Stack JavaScript Techdegree Student 11,638 Points
Aakash Srivastav
.a{fill-rule:evenodd;}techdegree
Aakash Srivastav
Full Stack JavaScript Techdegree Student 11,638 Points

Oh . Thanks
I just got confused with the word "const" , I forgot that the value gets stored in stack . And it also vanished into next repitition.
Thanks again .