Eryk Napierała

No one likes to wait. Even at a nice restaurant, if the food takes too long to arrive, you’ll start wriggling on your chair and looking around for the waiter. Worst case, you might even leave. 

This is nothing new: people are impatient by nature, and your users are no different. If you ask them to wait too long for their requested content, they’ll enjoy the experience less and eventually drop off.

In JavaScript, 'let' and 'const' bindings have a property called Temporal Dead Zone (TDZ). It’s a deadly trap indeed, and often not easy to spot. I learned this the hard way while working on JavaScript bundle optimization at Hotjar.