🧒 Explain like I'm 5
Imagine you have a sticky note that you can put on toys, but when you throw the toy away, the sticky note disappears too. WeakMap and WeakSet are like that—they hold information about things only as long as those things exist, so they don't prevent the garbage collector from cleaning up.
Interactive quiz
Check your understanding with an instant-feedback quick check.
Detailed notes
Senior-level deep dive: internals, pitfalls, and a self-interview ladder.
Practice with AI feedback
Answer out loud, get scored on correctness, depth, and clarity.