JavaScript ES6+ Features

Assess your knowledge of modern JavaScript features like arrow functions,destructuring,and modules.

1. Which keyword is used for block-scoped variable declaration in ES6?

var let function

2. Which of the following features were introduced in ES6 (2015)?

Arrow functions async/await Destructuring assignment Optional chaining (?.)

3. Arrow functions have their own 'this' binding.

True False

4. What characters are used to enclose template literals in ES6?

5. Which operator is used for the rest parameter syntax in ES6?

* & ... #

6. Which of these are valid uses of destructuring assignment in ES6?

Array destructuring Object destructuring Function parameter destructuring Class destructuring

7. const declarations create immutable values.

True False

8. What is the output of `[1, 2, 3].find(x => x > 2)`?

9. Which ES6 feature allows specifying default values for function parameters?

Rest parameters Default parameters Spread parameters Optional parameters

10. Which array methods were introduced in ES6?

find() map() entries() filter()

11. The spread operator (...) can be used to merge two arrays.

True False

12. What keyword is used to export a default value from an ES6 module?

13. What does the 'import' statement do in ES6 modules?

Declares a constant variable Loads and uses functionality from another module Defines a new function Creates an object

14. Which of the following are features of ES6 classes?

Constructor method Prototype methods Static methods Private fields (#)

15. ES6 introduced the 'Promise' object for asynchronous operations.

True False

16. What is the output of `const {x=10} = {x: undefined}; console.log(x)`?

17. Which ES6 feature provides a concise syntax for writing function expressions?

Generator functions Arrow functions Async functions Function declarations

18. Which of the following are valid ways to declare an ES6 class?

class MyClass {} const MyClass = class {} class MyClass extends OtherClass {} function MyClass() {}

19. Optional chaining (?.) was introduced in ES6.

True False

20. What operator is used for nullish coalescing in ES2020 (a post-ES6 feature)?

Answered 0 of 0 — 0 correct

Company