For loop is not iterating within setTimeout

Question

I'm trying to figure out why this for loop does not render out 0,1,2,3 like its suppose to.

It renders 4, 4 , 4, 4.

How would i get this to print 0, 1, 2, 3 with the setTimeout still in place ?

for (var i = 0; i < 4; i++) {   
    setTimeout(function() {     
        console.log('The index of this number is: ' + i);   
    }, 3000); 
}

it appears that by changing var to let it works, idk why this is the case. — randal, Mar 26 '19 at 17:46

score 1 · Answer 1 · answered Mar 26 '19 at 17:36

1

Create another and call it on each iteration

function a(i)
{
 setTimeout(function() {     
        console.log('The index of this number is: ' + i);   
    }, 3000); 
}

for (var i = 0; i < 4; i++) {   
   a(i);
}

answered Mar 26 '19 at 17:36

ellipsis

12,049
2
17
33

thanks, do you have a reason why the code that i posted does't print your solution ? – randal Mar 26 '19 at 17:40

For loop is not iterating within setTimeout

1 Answers1