JavaScript
31 practice items · needed by 4 roles
Easy 17Medium 7Hard 7
Practice questions
- Block scope of leteasy
- Loose vs strict equalityeasy
- Sync code runs before promise callbackseasy
- typeof null and arrayseasy
- Changing a property of a const objecteasy
- Numbers saved in localStorageeasy
- What fetch does on a 404easy
- Optional chaining on missing dataeasy
- ?? versus || with zeroeasy
- Order of click handlerseasy
- Sorting numbers without a comparatoreasy
- setTimeout vs microtasksmedium
- Closures in a var loopmedium
- Debounce vs throttle for searchmedium
- Arrow function as an object methodmedium
- Function hoisting and letmedium
- Spread copies only one levelmedium
- reduce on an empty arraymedium
- Losing this when a method is extractedhard
- Order of object keyshard
- map with parseInthard
- Comparator that returns a booleanhard
- fetch and error status codeseasy
- Timer vs promise ordereasy
- try/catch around an async calleasy
- map with an async callbackeasy
- Dates sent through JSONeasy
- Birthday shows one day earlyhard
- Large IDs change in the browserhard
- One failure in Promise.allhard
- toBe versus toEqualeasy