Extramarks Education Interview Questions, Process, and Tips

let is mutable and can be reassigned, const is immutable and cannot be reassigned

• let allows reassignment of values, const does not

• const must be initialized with a value, let can be declared without a value

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

Closures are functions that have access to variables from their containing scope even after the parent function has finished executing.

• Closures allow functions to maintain access to variables from their parent scope

• They are created when a function is defined within another function

• Closures are commonly used in event handlers and callbacks

typeof null returns 'object' in JavaScript.

• typeof null is 'object' in JavaScript

• This is a historical bug in JavaScript that has not been fixed for backward compatibility

• Example: console.log(typeof null) will output 'object'

Finding palindrome strings in an array of strings.

• Iterate through each string in the array.

• For each string, check if it is equal to its reverse to determine if it is a palindrome.

• Store palindrome strings in a separate array or print them out.

Debouncing is a technique used to limit the rate at which a function is called.

• Debouncing is used to prevent multiple rapid calls to a function, typically in response to user input.

• It involves setting a delay before allowing the function to be called again.

• Example: Debouncing a search input field to only trigger the search function after the user has stopped typing for a certain period.