ES6

Question 1

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

Answer 1

{Code inside curly braces that is meant to be grouped}

Question 2

What does block scope mean?

Answer 2

{everything within that specific code block}

Question 3

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

Answer 3

block scoped

Question 4

What is the difference between let and const?

Answer 4

let can be updated but not redeclared , const cannot be updated or re-declared

Question 5

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

Answer 5

possible to modify the contents.

Question 6

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

Answer 6

cant reassign const. Let is able to reassign.

Question 7

What is the syntax for writing a template literal?

Answer 7

• you create a template literal by wrapping your text in backticks
• Multiline string: a string that can span multiple lines.
• String formatting: the ability to substitute part of the string for the values of variables or expressions. This feature is also called string interpolation.
• HTML escaping: the ability to transform a string so that it is safe to include in HTML.

Question 8

What is “string interpolation”?

Answer 8

String formatting: the ability to substitute part of the string for the values of variables or expressions. This feature is also called string interpolation.

Question 9

What is destructuring, conceptually?

Answer 9

an alternative way to assign properties of an object to variables

Question 10

What is the syntax for Object destructuring?

Answer 10

• let{
  property1 : variable1,
  property2 : variable2
  } = object;

Question 11

What is the syntax for Array destructuring?

Answer 11

let [a,b,c] = function or object;

Question 12

How can you tell the difference between destructuring and creating Object/Array literals?

Answer 12

= object at the end

Question 13

What is the syntax for defining an arrow function?

Answer 13

var name = (parameters) => expression

Question 14

When an arrow function’s body is left without curly braces, what changes in its functionality?

Answer 14

dont need a return statement

Question 15

How is the value of this determined within an arrow function?

Answer 15

First, in the arrow function, the this, arguments, super, new.target are lexical. It means that the arrow function uses these variables (or constructs) from the enclosing lexical scope.