About this practice test
This practice test checks your working knowledge of modern JavaScript (ES6+), covering both the language itself and the browser and Node.js basics that come up in hiring tests and technical interviews.
What it covers
- Types, coercion, == vs ===, typeof, and truthy/falsy values
- var, let and const, hoisting, the temporal dead zone, scope and closures
- Functions, arrow functions, default and rest parameters, and this with call, apply and bind
- Objects, destructuring, spread, optional chaining, nullish coalescing, arrays and array-method pitfalls
- Prototypes, classes and inheritance
- Promises, async/await, error handling, and the event loop (microtasks vs macrotasks)
- ES modules vs CommonJS, DOM events (bubbling, delegation, preventDefault), browser storage, fetch, JSON and CORS basics
- Map, Set, Symbol, generators, debouncing and throttling
Who it is for
Freshers and early-career frontend and full-stack developers preparing for JavaScript rounds, online coding assessments and interviews.
Format
200 multiple-choice questions mixing output-prediction snippets ("what is logged?") with concept questions, at easy, medium and hard levels. Every question has a short explanation shown after you answer, including the common trap where there is one.
Free to attempt with a TestsWorld account. No card required.