Q
What happens if you access a var variable before its declaration in JavaScript?

Answer & Solution

Answer: Option C
Solution:
Accessing a var variable before its declaration in JavaScript results in the value undefined, as var variables are hoisted with an initial value of undefined.
Related Questions on Average

How can you avoid issues related to hoisting and TDZ in JavaScript?

A). A. Always declare variables at the bottom of the code

B). B. Use var for all variable declarations

C). C. Declare variables with let or const and avoid accessing them early

D). D. None of the above

What is hoisting in JavaScript?

A). A. A process of lifting heavy objects

B). B. Moving variable and function declarations to the top of their scope

C). C. Reducing code size

D). D. None of the above

What is the output of the following code snippet?

A). A. TypeError

B). B. 10

C). C. undefined

D). D. SyntaxError

Which keyword allows hoisting of variables in JavaScript?

A). A. var

B). B. let

C). C. const

D). D. Both A and B

How does hoisting affect arrow functions in JavaScript?

A). A. Arrow functions are hoisted with their function bodies

B). B. Arrow functions are hoisted but cannot be accessed before declaration

C). C. Arrow functions are not hoisted

D). D. Hoisting has no effect on arrow functions

How can you ensure that a const variable is initialized before use in JavaScript?

A). A. Use let instead of const for all variables

B). B. Declare const variables at the top of their scope

C). C. Assign a default value to const variables

D). D. None of the above

How does hoisting differ between let and var declarations in JavaScript?

A). A. Both let and var variables are hoisted with their initial values

B). B. let variables are hoisted with their initial values, var variables are hoisted with undefined

C). C. let variables are not hoisted, var variables are hoisted with their initial values

D). D. Hoisting behavior is the same for let and var declarations

What is the result of the following code snippet?

A). A. SyntaxError

B). B. ReferenceError

C). C. TypeError

D). D. No error

What happens if you try to reassign a const variable in JavaScript?

A). A. No effect on the variable

B). B. SyntaxError is thrown

C). C. ReferenceError is thrown

D). D. TypeError is thrown

How does hoisting affect variable shadowing in JavaScript?

A). A. It allows variables with the same name in different scopes to coexist

B). B. It prevents variables with the same name in different scopes from coexisting

C). C. It has no effect on variable shadowing

D). D. It automatically renames variables with the same name