Variable scope, closure

Question 1

{
let message = “Hello”; // only visible in this block
alert(message); // returns
}

Answer 1

hello

Question 2

{
let message = “Hello”; // only visible in this block
}

alert(message); // returns?

Answer 2

Error: message is not defined

Question 3

{
let message = “Hello”;
alert(message);
}

{
let message = “Goodbye”;
alert(message);
}

both return?

Answer 3

Hello
Goodbye

Question 4

let message = “Hello”;
alert(message);

let message = “Goodbye”;
alert(message);

Answer 4

// Error: variable already declared

Question 5

if (true) {
let phrase = “Hello!”;
alert(phrase); // return?
}

Answer 5

Hello

Question 6

if (true) {
let phrase = “Hello!”;
}

alert(phrase); //

Answer 6

Error, no such variable!

Question 7

The Lexical Environment object consists of two parts:

Answer 7

Environment Record – an object that stores all local variables as its properties (and some other information like the value of this).

A reference to the outer lexical environment, the one associated with the outer code.