es6-const-let

Question 1

What is a code block? What are some examples of a code block?

Answer 1

denoted by curly braces... examples include if statements, CSS rulesets, functions, loops
if ( ) { //code block//} ;
.ruleset {// code block//}
function ( ) {//code block// }
for ( ) {//code block//}

Question 2

What does block scope mean?

Answer 2

the variable defined within a block will not be accessible from outside the block- only accessible within that block

Question 3

What is the scope of a variable declared with const or let?

Answer 3

block scope, so depending on what point you are referencing it

Question 4

What is the difference between let and const?

Answer 4

let variables can be updated but not re-declared; const variables can neither be updated nor re-declared

Question 5

Why is it possible to .push() a new value into a const variable that points to an Array?

Answer 5

This happens because your constant is actually storing a reference to the array, so not changing the const but changing its reference

Question 6

How should you decide on which type of declaration to use?

Answer 6

Use let when you know that the value of a variable will change. Use const for every other variable.