Javascript questions

The difference between var, let, and const is that var is function-scoped, while let and const are block-scoped. Additionally, variables declared with const cannot be reassigned.

A closure is a function that has access to its own scope, the scope of the outer function, and the global scope.

The event loop is a mechanism that allows JavaScript to perform non-blocking operations by offloading operations to the system kernel whenever possible.

The == operator compares values for equality after converting both values to a common type, while === compares both values and types without conversion.

A promise is an object that represents the eventual completion (or failure) of an asynchronous operation and its resulting value.

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

Null is an assignment value that means "no value" and must be assigned, while undefined means a variable has been declared but not yet assigned a value.

The call() method calls a function with a given this value and arguments provided individually.

The apply() method calls a function with a given this value, and arguments provided as an array (or an array-like object).

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.