js-assignment-8.md

JavaScript Assignment #8: Callbacks

You will complete all of these challenges in the same file.

Challenge #1: Practice .filter()

• Make an array with the numbers 1 - 10
• Use .filter() to create an array with only numbers that are larger than 7
• Use .filter() to create an array with only numbers that are even
• Use .filter() to create an array with only numbers that are divisible by 3

Challenge #2: Practice .map()

Using that same array with number 1-10

• Use .map() to create an array with the square of each number (such as [1, 4, 9, 16...])
• Use .map() to create an array with each number halved (such as [0.5, 1, 1.5...])

Challenge #3: Using .filter() to filter objects

Start by pasting this into your code:

const prices = [
  { product: "shoes", price: 50, inStock: true },
  { product: "light bulb", price: 3, inStock: true },
  { product: "stuffed animal", price: 15, inStock: false },
  { product: "jacket", price: 75, inStock: false },
  { product: "keychain", price: 4, inStock: true },
]

• Use .filter() to create an array with only the product objects that cost less than $20
• Use .filter() to create an array with only the product objects that are in stock
• Use .filter() to create an array with only the product objects that are in stock AND cost less than $20

Challenge #4: Using .map() to map objects

• We're having a sale! Use .map() to create an array with all the same objects, but with the prices reduced by 25%
• The sale is only for products that cost more than $10. Rewrite the previous map to only change the prices for items with prices above $10.
• We're making an ad for the sale. Make an array of strings that read, for example, "shoes are on sale for only $37.50!"

Extra challenges (optional)

• Can you use .reduce() to join all the strings from the previous together into one long string?