Can you sit the JavaScript Certification today?

What does this log? ```js try { console.log("a"); missing(); console.log("b"); } catch { console.log("c"); } console.log("d"); ```

• Aa b c d
• Ba c d
• Ca c
• Da b d

What happens here? ```js const user = { name: "Asha" }; const { address: { city }, } = user; ```

• AIt throws a TypeError, because it tries to read city on undefined
• Bcity is undefined
• Ccity is an empty object
• DIt throws a ReferenceError, because address was never declared

What does the read cost here? ```js requestAnimationFrame(() => { el.style.transform = "translateX(100px)"; console.log(el.getBoundingClientRect().left); }); ```

• ANothing: reads inside an animation frame are served from the previous frame's cached layout
• BNothing, because a transform does not affect layout, so there is nothing to recompute
• CA full repaint, because getBoundingClientRect is a paint-time operation
• DA forced synchronous layout: the pending style change has to be flushed before an accurate box can be reported

What does this log? ```js function Point(x) { this.x = x; } const p = new Point(1); Point.prototype.show = function () { return this.x; }; console.log(p.show()); ```

• AIt throws a TypeError, because p was made before show existed
• Bundefined
• C1
• DThe function itself, because it was never called

A function re-queues itself endlessly with `setTimeout(loop, 0)`. Compared with the same function re-queuing itself with `queueMicrotask`, what happens to the tab?

• AIt hangs in the same way, because the task queue is also drained until it is empty
• BIt hangs sooner, because each timer callback also forces a layout
• CThe tab keeps rendering and responding: one task runs per turn, and nested timers are clamped to roughly 4 ms, so there is room in between
• DNothing happens at all, because a timer that reschedules itself is cancelled after a few rounds