| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 1 | Array.of vs the Array constructor | Arrays | Multiple choice | Medium |
| 2 | Flatten to any depth — no recursion allowed | Arrays | Coding | Medium |
| 3 | The default sort trap | Arrays | Multiple choice | Medium |
| 4 | Build a matrix with Array.from | Arrays | Coding | Medium |
| 5 | One-pass tokenizer with flatMap |
| Arrays |
| Coding |
| Medium |
| 6 | Numeric-preferred operators | Type Coercion | Multiple choice | Medium |
| 7 | var vs let in async loops | Quiz: JS Questions | Multiple choice | Medium |
| 8 | Arrow functions don't bind this | Quiz: JS Questions | Multiple choice | Medium |
| 9 | Hoisting and the temporal dead zone | Quiz: JS Questions | Multiple choice | Medium |
| 10 | Math.max edge cases | Math | Multiple choice | Medium |
| 11 | Max of a nested structure — no loops | Math | Coding | Medium |
| 12 | Swap two values without a temp variable | Destructuring | Coding | Medium |
| 13 | Dissect a URL with new URL() | URL & Web APIs | Coding | Medium |
| 14 | Mitigating cross-site scripting | Security | Multiple choice | Medium |
| 15 | for…in vs for…of on arrays | Loops | Multiple choice | Medium |
| 16 | Reverse an integer with do…while | Loops | Coding | Medium |
| 17 | Collatz stopping time with while | Loops | Coding | Medium |
| 18 | for…of with entries() and destructuring | Loops | Coding | Medium |
| 19 | unknown vs any | TypeScript | Multiple choice | Medium |
| 20 | The get trap intercepts everything | Proxy & Reflect | Multiple choice | Medium |
| 21 | Auto-vivifying counter (defaultdict) | Proxy & Reflect | Coding | Medium |
| 22 | typeof's famous lies | YDKJS Book | Multiple choice | Medium |
| 23 | The module pattern: private state via closure | YDKJS Book | Coding | Medium |
| 24 | Automatic Semicolon Insertion strikes | YDKJS Book | Multiple choice | Medium |
| 25 | once(fn) — run exactly one time | YDKJS Book | Coding | Medium |
| 26 | b + a + + a + a | WTF Quirks | Multiple choice | Medium |
| 27 | Comparison chains don't chain | WTF Quirks | Multiple choice | Medium |
| 28 | Math.min() > Math.max() | WTF Quirks | Multiple choice | Medium |
| 29 | Spread and rest, everywhere at once | Quiz: JS Questions | Multiple choice | Medium |
| 30 | Symbols hide from everything | Quiz: JS Questions | Multiple choice | Medium |