JavaScript & TypeScript Questions

This repository contains questions on JavaScript and TypeScript, which were originally published in the form of quizzes in the telegram channel https://t.me/intspirit.

A typical question is what the given piece of code will output. However, there are others. For example, the memory-usage and optimization folders contain questions about memory leaks, the performance of a particular piece of code, and more.

Use these questions to prepare for an interview or to test your language skills.

Each question is contained in a separate file.

In the comment to the question there is a link to an explanation of the problem. Even if you answered the question correctly, it is recommended to read the explanation, because it may reveal additional interesting details.

Example

function log(arg) {
  console.log(arg);
}

log(...'abc');

// What will be the output?

// Try yourself and read the explanation: https://t.me/intspirit/626?comment=674

If you follow the link, you will read this explanation:

The spread (...) syntax allows an iterable, such as string or array, to be expanded in function call's arguments list.

log(...'abc')

is equivalent to

log('a', 'b', 'c');

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

Categories of questions

The repository is live and will be regularly updated with new challenges. The repository currently contains questions in the following categories:

JavaScript

1. Arguments
2. Algorithms
3. Arrays
4. Classes
5. Context
6. Destructoring & rest & spread
7. ES6 modules
8. Event loop
9. Html events
10. Generators
11. JSON
12. Map & WeakMap
13. Memory usage
14. Objects
15. Performance
16. Promises
17. Prototypes
18. Set
19. Strings
20. Symbols
21. Type coercion
22. Variable scope
23. Workers
24. Other

TypeScript

Let's learn the language we use every day.

Let's make IT better!