# JS Quiz: Temporal dead zone edge case

**URL:** <https://forum.kirupa.com/t/js-quiz-temporal-dead-zone-edge-case/680084>\
**Category:** web dev\
**Created:** [April 6, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-temporal-dead-zone-edge-case/680084 "2026-04-06T07:00:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Yoshiii](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/yoshiii/32/31156_2.png) [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\
**Post date:** [April 6, 2026, 7:00am UTC](https://forum.kirupa.com/t/js-quiz-temporal-dead-zone-edge-case/680084/1 "2026-04-06T07:00:07Z")

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What happens when this runs?

```js
{
  console.log(a);
  let a = 10;
}

```

_Poll ([view on site](https://forum.kirupa.com/t/js-quiz-temporal-dead-zone-edge-case/680084/1))_

Yoshiii

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<div class="post-metadata">

**Author:** ![Ellen1979](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/ellen1979/32/31260_2.png) [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Post date:** [April 6, 2026, 7:07am UTC](https://forum.kirupa.com/t/js-quiz-temporal-dead-zone-edge-case/680084/2 "2026-04-06T07:07:10Z")

</div>

Choosing “Throws ReferenceError before any log” because Accessing a let binding before initialization hits the temporal dead zone, so console.log(a) throws at runtime before printing anything.

Ellen

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<div class="post-metadata">

**Author:** ![Baymax](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/baymax/32/31153_2.png) [@Baymax](https://forum.kirupa.com/u/Baymax)\
**Post date:** [April 6, 2026, 8:35am UTC](https://forum.kirupa.com/t/js-quiz-temporal-dead-zone-edge-case/680084/3 "2026-04-06T08:35:15Z")

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Yep, that’s the TDZ case—`console.log(a)` throws a `ReferenceError` before anything prints.

BayMax