Which statement about var, let, and const is true?

Which statement about var, let, and const is true?

• A. Let is block-scoped and can be reassigned.
• B. Var is block-scoped and cannot be redeclared.
• C. Const is block-scoped and can be redeclared.
• D. Let is block-scoped and can be redeclared in the same scope.

Answer: (A)

Understanding how variable declarations behave with var, let, and const in JavaScript. The statement that let is block-scoped and can be reassigned is true. Block scope means the binding is only visible inside the nearest pair of curly braces, such as inside a function, loop, or conditional block. Because of this scope, a let variable is not accessible outside that block. It can be assigned a new value later, which is what “can be reassigned” expresses. At the same time, you cannot redeclare the same binding with let in the same scope, which helps prevent accidental redefinitions. Why the other points aren’t correct: var is not block-scoped; it’s function-scoped (or globally scoped if declared outside a function), and it can be redeclared in the same scope. Const is block-scoped like let but cannot be reassigned after its initial binding (though, for objects, the contents can still be mutated). And letting a binding be redeclared in the same scope with let is not allowed, which is why that statement is false.

Understanding how variable declarations behave with var, let, and const in JavaScript. The statement that let is block-scoped and can be reassigned is true. Block scope means the binding is only visible inside the nearest pair of curly braces, such as inside a function, loop, or conditional block. Because of this scope, a let variable is not accessible outside that block. It can be assigned a new value later, which is what “can be reassigned” expresses. At the same time, you cannot redeclare the same binding with let in the same scope, which helps prevent accidental redefinitions.

Why the other points aren’t correct: var is not block-scoped; it’s function-scoped (or globally scoped if declared outside a function), and it can be redeclared in the same scope. Const is block-scoped like let but cannot be reassigned after its initial binding (though, for objects, the contents can still be mutated). And letting a binding be redeclared in the same scope with let is not allowed, which is why that statement is false.