What will const x = { a: 1 }; x.a = 2; do?

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;

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

Which operator assigns a remainder to a variable?

A). +=

B). -=

C). *=

D). %=

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 be the output of let { a, b } = { a: 1, b: 2, c: 3 };?

A). a is 1, b is 2

B). a is 2, b is 3

C). a is 1, b is undefined

D). a is 3, b is undefined

Can a constant objects properties be changed?

A). Yes

B). No

C). Only if redeclared

D). Only with special methods

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

What does the assignment operator = do in JavaScript?

A). Compares two values

B). Assigns a value to a variable

C). Checks for equality

D). None of the above

How to increment a variable count by 1?

A). count + 1

B). count += 1

C). count =+ 1

D). count = 1

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