What does const do in JavaScript?
A). Declares a block-scoped variable
B). Declares a constant value
C). Declares a global variable
D). Declares a function
What is the equivalent of x *= 4?
A). x = x + 4
B). x = x / 4
C). x = x * 4
D). x = 4
What does let { a: alpha, b: beta } = { a: 1, b: 2 }; do?
A). Creates variables alpha and beta with values 1 and 2
B). Creates variables a and b with values 1 and 2
C). Throws an error
D). Assigns default values
Which operator assigns a remainder to a variable?
A). +=
B). -=
C). *=
D). %=
Can a constant objects properties be changed?
A). Yes
B). No
C). Only if redeclared
D). Only with special methods
What will be the value of x after the following code: let x = 10; x += 5;
A). 5
B). 10
C). 15
D). 20
How can you swap the values of two variables a and b in one line?
A). [a, b] = [b, a]
B). a = b, b = a
C). a == b, b == a
D). a === b, b === a
How do you assign default values in destructuring?
A). let { a, b } = { a: 1 };
B). let { a = 1, b = 2 } = {};
C). let [a, b] = [1, 2];
D). let { a, b } = { a: 1, b: 2 };
Which assignment will fail?
A). const x = 10; x = 20;
B). let y = 5; y = 10;
C). var z = 15; z = 30;
D). let a = { b: 2 }; a.b = 3;
How to use destructuring to extract properties from an object?
A). { a, b } = { a: 1, b: 2 }
B). let { a, b } = { a: 1, b: 2 };
C). let a, b = { a: 1, b: 2 };
D). let (a, b) = { a: 1, b: 2 };