I have a file in c:\jsdev\ folder called script.js

with this source code:

const arr = [3, 'myStr', 5, 7];
arr.foo = 'hello';

for (let i in arr) {
  console.log(i); // logs "0", "1", "2", "foo"
}

console.log(arr);

When I run this in cmd

c:\jsdev>node script.js

I get following output

0
1
2
3
foo
[ 3, 'myStr', 5, 7, foo: 'hello' ]

Picture of my cmd shell in Windows 10

But when I press the Run code snippet (try it out now in stackoverflow), it just outputs

[ 3, 'myStr', 5, 7 ]