What will be the value of x after the following code: let x = 10; x += 5;
A). 5
B). 10
C). 15
D). 20
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
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 };
What will be the result of let { a, b } = { a: 3, b: 4 };?
A). a is 4, b is 3
B). a is 3, b is 4
C). a is undefined, b is undefined
D). a is null, b is null
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 const x = { a: 1 }; x.a = 2; do?
A). Throw an error
B). Change x.a to 2
C). Change x to 2
D). Do nothing
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 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 };
What will let x = 5, y = 10; [x, y] = [y, x]; do?
A). Nothing
B). Throws an error
C). Swaps values of x and y
D). None of the above