JavaScript Quiz

What is the main difference between let and const?

• let is block-scoped, const is global-scoped

• let can be reassigned, const cannot

• let creates immutable variables, const creates mutable ones

• let is function-scoped, const is block-scoped

Which method is used to make HTTP requests with Axios?

• axios.get()

• axios.fetch()

• axios.request()

• axios.http()

What will this code output? console.log(typeof null);

• "null"

• "object"

• "undefined"

• "string"

Which function is an example of a recursive function?
function countdown(num) {

if (num <= 0) return;

console.log(num);

countdown(num - 1);

}

• Yes

• No

Which of the following is NOT a valid HTTP method?

• PATCH

• FETCH

• PUT

• DELETE

What is the purpose of JSON.parse()?

• Converts an object to a string

• Parses a string into a JSON object

• Fetches data from an API

• Validates JSON syntax

What is a higher-order function?

• A function that only works with arrays

• A function that returns an object

• A function that takes another function as an argument or returns a function

• A function that executes immediately

Which statement is true for JavaScript promises?

• A promise can only resolve

• A promise can only reject

• A promise has three states: pending, fulfilled, rejected

• A promise blocks the main thread

How do you call an API with the Fetch API?

• apiCall()

• http.fetch()

• fetch()

• callAPI()

What is the output of this code? console.log(1 + "2" + 3);

• 6

• "123"

• 15

• NaN