| 1 | How does PHP's type coercion behave differently in strict types mode compared to the default coercive mode, and what are the implications for function argument and return type validation? PHP › Basics & Types | PHP | Basics & Types | Advanced |
| 2 | What makes an object 'iterable' in JavaScript? JavaScript › Iterators & Generators | JavaScript | Iterators & Generators | Beginner |
| 3 | How do you write a basic generator function? JavaScript › Iterators & Generators | JavaScript | Iterators & Generators | Beginner |
| 4 | How does JavaScript decide when to free memory used by an object? JavaScript › Memory Management & Garbage Collection | JavaScript | Memory Management & Garbage Collection | Beginner |
| 5 | Why does 0.1 + 0.2 not equal 0.3 exactly in JavaScript? JavaScript › Numbers, Math & BigInt | JavaScript | Numbers, Math & BigInt | Beginner |
| 6 | What does Array.isArray() solve that typeof can't? JavaScript › Arrays & Array Methods | JavaScript | Arrays & Array Methods | Intermediate |
| 7 | How do you format numbers and currency for a locale using Intl.NumberFormat? JavaScript › Date, Time & Internationalization (Intl API) | JavaScript | Date, Time & Internationalization (Intl API) | Intermediate |
| 8 | Why does 9007199254740993n + 1 throw a TypeError, but 9007199254740993n + 1n does not? JavaScript › Numbers, Math & BigInt | JavaScript | Numbers, Math & BigInt | Intermediate |
| 9 | How can you use destructuring to swap two variables without a temporary variable? JavaScript › Destructuring, Spread & Rest | JavaScript | Destructuring, Spread & Rest | Advanced |
| 10 | Why is Number.parseFloat('123abc') valid but Number('123abc') returns NaN? JavaScript › Numbers, Math & BigInt | JavaScript | Numbers, Math & BigInt | Advanced |