| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 1 | + concatenates, - calculates | Type Coercion | Multiple choice | Easy |
| 2 | Truthy or falsy? | Type Coercion | Multiple choice | Easy |
| 3 | typeof, the basics | Quiz: JS Questions | Multiple choice | Easy |
| 4 | What const actually locks | Quiz: JS Questions | Multiple choice | Easy |
| 5 | floor, ceil, round |
| Math |
| Multiple choice |
| Easy |
| 6 | The safe way to show user text | Security | Multiple choice | Easy |
| 7 | typeof narrowing 101 | TypeScript | Multiple choice | Easy |
| 8 | A Proxy with no traps | Proxy & Reflect | Multiple choice | Easy |
| 9 | Turning strict mode on | Strict Mode | Multiple choice | Easy |
| 10 | A closure remembers | YDKJS Book | Multiple choice | Easy |
| 11 | NaN is not NaN | WTF Quirks | Multiple choice | Easy |
| 12 | Spot the anti-pattern: == everywhere | Patterns & Performance | Multiple choice | Easy |
| 13 | Spot the anti-pattern: var in 2026 | Patterns & Performance | Multiple choice | Easy |
| 14 | Copy or alias? | Patterns & Performance | Multiple choice | Easy |
| 15 | Factory functions vs constructors | Patterns & Performance | Multiple choice | Easy |
| 16 | localStorage, sessionStorage, cookies | Web Platform | Multiple choice | Easy |
| 17 | The call stack: push, run, pop | Event Loop & Memory | Multiple choice | Easy |
| 18 | Reading a var before its line | Scope & Hoisting | Multiple choice | Easy |
| 19 | Reading a let before its line | Scope & Hoisting | Multiple choice | Easy |
| 20 | Calling a function above its declaration | Scope & Hoisting | Multiple choice | Easy |
| 21 | Calling a function expression above its line | Scope & Hoisting | Multiple choice | Easy |
| 22 | var leaks, let doesn't | Scope & Hoisting | Multiple choice | Easy |
| 23 | target vs currentTarget | DOM Events | Multiple choice | Easy |
| 24 | The once option | DOM Events | Multiple choice | Easy |
| 25 | Smuggling data in CustomEvent | DOM Events | Multiple choice | Easy |
| 26 | Removing a listener you can't name | DOM Events | Multiple choice | Easy |
| 27 | beforeAll vs beforeEach: the run count | Testing Lifecycle | Multiple choice | Easy |
| 28 | Does cleanup run when the test fails? | Testing Lifecycle | Multiple choice | Easy |