Array filter

Using filter

We can use a function which returns true and false to remove items from an array.

js

const pageNumbers = [300, 150, 120, 500, 250]

const shortBooks = pageNumbers.filter(num => num < 200)
console.log(shortBooks)

output

[ 150, 120 ]

Combining with map

We can chain together .map() and .filter() to transform an array several times.

js

const pageNumbers = [300, 150, 120, 500, 250]

const quickReads = pageNumbers
  .filter(num => num < 200)
  .map(num => (num * 1.5) / 60 + ' hours')

output

[ '3.75 hours', '3 hours' ]