CodeParkfor (var i = 0; i < 3; i++) {
setTimeout(() => console.log(i), 0);
}
3 3 3
var creates one function-scoped i that all three callbacks share. The callbacks run after the loop has finished, and by then i is already 3. So each one logs 3.
The tempting option "0 1 2" is wrong for var. You would get 0 1 2 with let, because let creates a new i for each loop iteration.