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
What will be the output of the following code: if (true) { let b = 60; } console.log(b);
A). 60
B). undefined
C). Error
D). null
What will be the output of the following code: var e = 110; if (true) { var e = 120; } console.log(e);
A). 110
B). 120
C). Error
D). undefined
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 is the default scope of variables declared with the 'var' keyword in JavaScript?
A). Block scope
B). Function scope
C). Module scope
D). Block and function scope
Which keyword is used for declaring variables that should not change?
A). var
B). let
C). const
D). all of the above
How do 'var' declarations handle hoisting?
A). They are not hoisted
B). Only the assignment is hoisted
C). Only the declaration is hoisted
D). Both declaration and assignment are hoisted
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
Which keyword allows block-scoped variable declaration?
A). var
B). let
C). const
D). Both B and C
What will be the output of the following code: const z = 30; z = 40; console.log(z);
A). 30
B). 40
C). Error
D). undefined