| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 31 | Symbols hide from everything | Quiz: JS Questions | Multiple choice | Medium |
| 32 | Static methods don't reach instances | Quiz: JS Questions | Multiple choice | Medium |
| 33 | null >= 0 but null != 0 | Type Coercion | Multiple choice | Hard |
| 34 | The army of things equal to nothing | Type Coercion | Multiple choice | Hard |
| 35 | '10' < '9' — string comparison traps |
| Type Coercion |
| Multiple choice |
| Hard |
| 36 | {} + [] — position is everything | Type Coercion | Multiple choice | Hard |
| 37 | Symbols: explicit yes, implicit never | Type Coercion | Multiple choice | Hard |
| 38 | Loose equality is not transitive | Type Coercion | Multiple choice | Hard |
| 39 | + concatenates, - calculates | Type Coercion | Multiple choice | Easy |
| 40 | Truthy or falsy? | Type Coercion | Multiple choice | Easy |
| 41 | typeof, the basics | Quiz: JS Questions | Multiple choice | Easy |
| 42 | What const actually locks | Quiz: JS Questions | Multiple choice | Easy |
| 43 | floor, ceil, round | Math | Multiple choice | Easy |
| 44 | The safe way to show user text | Security | Multiple choice | Easy |
| 45 | typeof narrowing 101 | TypeScript | Multiple choice | Easy |
| 46 | A Proxy with no traps | Proxy & Reflect | Multiple choice | Easy |
| 47 | Turning strict mode on | Strict Mode | Multiple choice | Easy |
| 48 | A closure remembers | YDKJS Book | Multiple choice | Easy |
| 49 | NaN is not NaN | WTF Quirks | Multiple choice | Easy |
| 50 | Spot the anti-pattern: == everywhere | Patterns & Performance | Multiple choice | Easy |
| 51 | Spot the anti-pattern: var in 2026 | Patterns & Performance | Multiple choice | Easy |
| 52 | Copy or alias? | Patterns & Performance | Multiple choice | Easy |
| 53 | The accidentally quadratic accumulator | Patterns & Performance | Multiple choice | Medium |
| 54 | Plain object or Map? | Patterns & Performance | Multiple choice | Medium |
| 55 | Hidden classes: the shape game | Patterns & Performance | Multiple choice | Hard |
| 56 | Four duplicates checks, one is optimal | Patterns & Performance | Multiple choice | Hard |
| 57 | Factory functions vs constructors | Patterns & Performance | Multiple choice | Easy |
| 58 | script: async vs defer | Web Platform | Multiple choice | Medium |
| 59 | What triggers a CORS preflight? | Web Platform | Multiple choice | Hard |
| 60 | no-cache does not mean no cache | Web Platform | Multiple choice | Hard |