Thought so as well first. But then again, you can write for (let i=0; i<10; i++) { console.log(i); i++; } And it correctly logs "1 3 5 7 9". So i

Thought so as well first. But then again, you can write for (let i=0; i<10; i++) { console.log(i); i++; } And it correctly logs "1 3 5 7 9". So if anything, the desugaring would have to be something like for (var _i=0; _i<3; _i++) { let i = _i; setInterval(() => {console.log(i); i+=100}, 1000); _i = i; } Haven't tried out putting closures inside the condition or incrementer to see if things get even weirder.