Quick JavaScript Crash Course - Modern and Advanced JavaScript - Var Keyword

The video tutorial discusses the WAR keyword in JavaScript, highlighting its historical significance and the issues it presents due to its lack of block scope. The tutorial explains different types of scope in JavaScript, such as global, function, and block scope, and demonstrates the problems WAR causes in loops and closures. The video concludes by hinting at how let and const can address these issues.

What was the primary use of the 'var' keyword in JavaScript historically?

• To declare functions

• To manage memory

• To define constants

• To create variables

Which type of scope does the 'var' keyword not adhere to?

• Global scope

• Function scope

• Local scope

• Block scope

What is the expected behavior when trying to access a variable declared with 'var' inside a function, from outside the function?

• The variable is accessible

• The variable is not defined

• The variable is undefined

• The variable is null

What is an IIFE and how is it related to 'var'?

• A function that is used to handle errors

• A function that is immediately invoked to create block scope

• A function that is used to declare variables

• A function that is used to manage memory

What happens when you try to access a 'var' variable declared inside a loop, from outside the loop?

• The variable is not accessible

• The variable is null

• The variable is accessible

• The variable is undefined

Why does the 'setTimeout' function in a loop with 'var' not behave as expected?

• Because 'setTimeout' is asynchronous

• Because 'setTimeout' is synchronous

• Because 'var' is function scoped

• Because 'var' is block scoped

What is a closure in JavaScript?

• A function that can access variables from its own scope

• A function that can access variables from any scope

• A function that can access variables from its parent scope

• A function that can access variables from the global scope

How does a closure relate to the 'var' keyword?

• It allows 'var' to be function scoped

• It allows 'var' to be block scoped

• It allows 'var' to be globally scoped

• It allows 'var' to maintain a reference to its environment

What is the main issue with 'var' in terms of scope?

• It is always globally scoped

• It is not block scoped

• It is not function scoped

• It is always block scoped

What is the expected output when a 'var' variable is accessed in a closure?

• The initial value of the variable

• The final value of the variable

• Undefined

• An error