Functions

Question 1

Arrow Functions (ES6)

Answer 1

Does not require the ‘function’ keyword, and uses a fat arrow (=>) to separate the parameters from the body

Arrow functions with a single parameter do not need () around the parameter list
const checkAge = age => { //do something}

Arrow functions with a single expression do not require the use of the return keyword
const multiple = (a, b) => a*b;

Question 2

Anonymous Functions

Answer 2

Functions that do not have a name property

const rocketToMars = function() {
return ‘BOOM!’;
}

Question 3

Function Expression

Answer 3

Create functions inside an expression instead of as a function declaration. They can be anonymous and/or assigned to a value

const dog = function() {
return ‘Woof!’;
}

const dog = () => ‘Woof!’;

Question 4

Parameters

Answer 4

Used as variables inside the function body
When a function is called, these parameters will have the value of whatever is passed in as arguments

function sayHello(name) {
return Hello, ${name}!;
}

Question 5

return

Answer 5

Used to return (pass back) values from functions

If a return value is not specified, the function will return undefined by default

Question 6

Calling functions

Answer 6

Functions can be called or executed using parentheses following the function name

// Defining the function
function sum(num1, num2) {
return num1 + num2;
}

// Calling the function
sum(2, 4); // 6

Question 7

Global Scope

Answer 7

A value/function in the global scope can be used anywhere in the entire program

Variables declared outside of blocks or functions exist in the global scope

Question 8

File/Module Scope

Answer 8

A value/function in the file/module scope can only be accessed within that file

Question 9

Block Scope

Answer 9

A value/function is only visible/accessible within a code block { … }

const and let are block-scoped variables