en.javascript.info/1-js/06-advanced-functions/03-closure/1-counter-independent/task.md
Ilya Kantor ab9ab64bd5 up
2017-03-21 14:41:49 +03:00

516 B

importance: 5


Are counters independent?

Here we make two counters: counter and counter2 using the same makeCounter function.

Are they independent? What is the second counter going to show? 0,1 or 2,3 or something else?

function makeCounter() {
  let count = 0;

  return function() {
    return count++;
  };
}

let counter = makeCounter();
let counter2 = makeCounter();

alert( counter() ); // 0
alert( counter() ); // 1

*!*
alert( counter2() ); // ?
alert( counter2() ); // ?
*/!*