why its output is 10???

Question

for(var i = 0;i < 10;i++)
setTimeout(() => {
console.log(i)
}, i * 1000);

Answer 1

Shushan , it's normal behavior if we consider the setTimeout method. There is call to a anonymous function inside the loop, which is executed after the delay i* 1000 ms =>i * 1s (on each step the timeout is updated with new value => 0s, 1s,..., 9s) . So the final value of i is 10=> which is printed on console in fact 10 times. You can find more info about this method here: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setTimeout

Answer 2

But if I wiIl write let instead of var it will work like I said from 0 to 9 ...
the problem here is var

Answer 3

Shushan , let declares block scope variable, var function scope variable. You can find more info here: https://www.google.com.br/amp/s/www.geeksforgeeks.org/difference-between-var-and-let-in-javascript/amp/

Answer 4

It will create error.

Answer 5

just your output is 0_9. if you wanna print output 10 you should write 1<=10

Answer 6

Mirielle from 0 to 9

Answer 7

Mirielle , I think it is just a challenge question in JS. I met this question a few times.

Answer 8

Mirielle , yes I think the question is about maybe the strange output at first sight 😺

Answer 9

TheWh¡teCat thanx🙂

Answer 10

Shushan , you are welcome 😺