Answer & Solution
Answer: Option A
Solution:
Declaring a variable without 'var', 'let', or 'const' creates a global variable, which can lead to potential bugs.
Q
What will happen if you declare a variable without 'var', 'let', or 'const'?
Related Questions on Average
Can 'const' be used to declare an array or object?
A). No, only primitives
B). Yes, but the reference can't change
C). Yes, and the content can't change
D). No
What will be the output of the following code: console.log(a); var a = 50;
A). 50
B). undefined
C). Error
D). null
What will be the output of the following code: var x = 5; var x = 10; console.log(x);
A). 5
B). 10
C). Error
D). undefined
Which keyword allows block-scoped variable declaration?
A). var
B). let
C). const
D). Both B and C
How does 'let' handle variable re-declaration in the same scope?
A). Allows it
B). Silently ignores
C). Throws an error
D). Creates a new variable
What will be the output of the following code: const d = 90; d = 100; console.log(d);
A). 90
B). 100
C). Error
D). undefined
How does 'let' differ from 'var' in terms of scope?
A). No difference
B). Function-scoped
C). Block-scoped
D). Global-scoped
Which keyword is used for declaring variables that should not change?
A). var
B). let
C). const
D). all of the above
What will be the output of the following code: let c = 70; { let c = 80; console.log(c); } console.log(c);
A). 70 80 80
B). 80 80
C). Error
D). 70 80
What is the scope of a variable declared with 'let' inside a loop?
A). Global
B). Function
C). Loop block
D). Entire script