Arrays and Objects

Question 1

What data type is the following:
let colors = ['blue', 'green', 'purple']

Answer 1

Array

Question 2

What data type is the following:
let colors = {'blue', 'green', 'purple'}

Answer 2

Object

Question 3

What will be console logged?
let dogs = ['Husky', 'Shiba Inu', 'Beagle', 'Dalmatian']
console.log( dogs[1] )

Answer 3

Shiba Inu

Question 4

What index number do arrays start at?

Answer 4

0

Question 5

Which array method will append something to the end of an array?

Answer 5

.push( )

Example Usage: 
let dogs = ['Husky', 'Shiba Inu', 'Beagle', 'Dalmatian'];
dogs.push('Golden Retriever');

Question 6

Which array method can be used to cut something out of an array and add something else?

Answer 6

.splice( )

Example Usage:
let dogs = ['Husky', 'Shiba Inu', 'Beagle', 'Dalmatian']
dogs.splice(0, 1, 'Corgi')
//This will remove Husky and replace it with Corgi

Question 7

The array method .splice( ) takes in three parameters. What is the purpose of each of these three parameters?

Answer 7

Array.splice(position, how many to cut, what to add in that location)

Question 8

What array method can be used to remove the last element of an array?

Answer 8

.pop( )

Example Usage:
let characters = ['Mario', 'Luigi', 'Yoshi', 'Peach']
characters.pop( )
//This will remove Peach

Question 9

What array method can be used to remove the first item of an array?

Answer 9

. shift( )

Example Usage: 
let characters = ['Mario', 'Luigi', 'Yoshi', 'Peach']
characters.shift( )
//This will remove Mario

Question 10

What will happen in the following code:
let characters = ['Mario', 'Luigi', 'Yoshi', 'Peach']
characters.unshift('Bowser', 'Wario')

Answer 10

It will add Bowser and Wario to the beginning of the array

[‘Bowser’, ‘Wario’, ‘Mario’, ‘Luigi’, ‘Yoshi’, ‘Peach’]

Question 11

What are the three arguments for a forEach( )

Answer 11

1. ) currentValue = the current element being processed in the array
2. ) index = the index of the current element being processed
3. ) array = the array the forEach method was called upon

Question 12

What is the syntax for a forEach( ) that will console log each of the items in this array?
let characters = ['Mario', 'Luigi', 'Yoshi', 'Peach']

Answer 12

characters.forEach(c => { console.log(c); })

Question 13

What will this console log?
let food = [‘Pizza’, ‘Pasta’, ‘Hamburger’, ‘Chips’, ‘Ice Cream’]
console.log(food.length)

Answer 13

5

Question 14

How would you step through this object and console log ‘fire’?

let pokemon = {
name: 'Bulbasaur',
id: 1,
type: ['grass', 'poison'],
weakness: ['psychic', 'flying', 'fire', 'ice'],
evolvesTo: 'Ivysaur',
description: 'A strange seed was planted on its back at birth. The plant sprouts and grows with this Pokémon.' 
}

Answer 14

console.log(pokemon.weakness[2])

Question 15

What does JSON stand for?

Answer 15

JavaScript Object Notation