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 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

Which keyword allows hoisting of variables in JavaScript?

A). A. var

B). B. let

C). C. const

D). D. Both A and B

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 behavior of accessing a const variable within a function before its declaration in JavaScript?

A). A. ReferenceError is thrown

B). B. SyntaxError is thrown

C). C. undefined is printed

D). D. No error

What is the result of the following code snippet?

A). A. SyntaxError

B). B. ReferenceError

C). C. TypeError

D). D. No error

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

What is the behavior of accessing a const variable before its declaration in a nested block in JavaScript?

A). A. ReferenceError is thrown

B). B. SyntaxError is thrown

C). C. undefined is printed

D). D. No error

What is the purpose of the Temporal Dead Zone (TDZ) in JavaScript?

A). A. To prevent variable reassignment

B). B. To catch errors at compile time

C). C. To ensure variables are initialized before use

D). D. To reduce memory usage

How does hoisting affect const declarations in JavaScript?

A). A. const variables are hoisted with their initial values

B). B. const variables are hoisted but cannot be accessed before declaration

C). C. const variables are hoisted and can be accessed before declaration

D). D. Hoisting does not affect const declarations