| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 1 | Array.of vs the Array constructor | Arrays | Multiple choice | Medium |
| 2 | Array.prototype.at is generic | Arrays | Multiple choice | Hard |
| 3 | Flatten to any depth — no recursion allowed | Arrays | Coding | Medium |
| 4 | Pair sum detection with .some() only | Arrays | Coding | Hard |
| 5 | Matrix validation with .every() |
| Arrays |
| Coding |
| Hard |
| 6 | Function composition with reduceRight | Arrays | Coding | Hard |
| 7 | The default sort trap | Arrays | Multiple choice | Medium |
| 8 | Sparse arrays and holes | Arrays | Multiple choice | Hard |
| 9 | Build a matrix with Array.from | Arrays | Coding | Medium |
| 10 | One-pass tokenizer with flatMap | Arrays | Coding | Medium |
| 11 | The + operator: string context wins | Type Coercion | Multiple choice | Hard |
| 12 | Numeric-preferred operators | Type Coercion | Multiple choice | Medium |
| 13 | The == algorithm, step by step | Type Coercion | Multiple choice | Hard |
| 14 | Take control of ToPrimitive | Type Coercion | Coding | Hard |
| 15 | var vs let in async loops | Quiz: JS Questions | Multiple choice | Medium |
| 16 | Arrow functions don't bind this | Quiz: JS Questions | Multiple choice | Medium |
| 17 | Hoisting and the temporal dead zone | Quiz: JS Questions | Multiple choice | Medium |
| 18 | Microtasks vs macrotasks | Quiz: JS Questions | Drag & drop | Hard |
| 19 | Math.max edge cases | Math | Multiple choice | Medium |
| 20 | Max of a nested structure — no loops | Math | Coding | Medium |
| 21 | Swap two values without a temp variable | Destructuring | Coding | Medium |
| 22 | Group transactions by risk bucket | Objects | Coding | Hard |
| 23 | What Object.groupBy actually returns | Objects | Multiple choice | Hard |
| 24 | Dissect a URL with new URL() | URL & Web APIs | Coding | Medium |
| 25 | Relative URL resolution | URL & Web APIs | Multiple choice | Hard |
| 26 | Mitigating cross-site scripting | Security | Multiple choice | Medium |
| 27 | Which sink executes? | Security | Multiple choice | Hard |
| 28 | for…in vs for…of on arrays | Loops | Multiple choice | Medium |
| 29 | Reverse an integer with do…while | Loops | Coding | Medium |
| 30 | Labeled break out of nested loops | Loops | Coding | Hard |