JavaScript Array Iterator Methods .map()

Learning objective: By the end of this lesson, students will be able to use map() to iterate over an array, creating a new modified array.

map

PURPOSE: Create a new array from a source array, usually “transforming” its values.

The returned array is always the same length as the source array.

const nums = [1, 2, 3]
const squared = nums.map((num) => {
  return num * num
});

// squared --> [1, 4, 9]

map returns a new array comprised of ‘transformed’ values - and how they have been transformed is up to the code we write in the callback function.

🎓 You Do

Given an array of instructors,

const instructors = ['Beryl', 'Hunter', 'Joe', 'Jurgen', 'Ben', 'David']

Use map to create a new array that adds the string “ is awesome” to each array element.

Sample output:

[
  'Beryl is awesome',
  'Hunter is awesome',
  'Joe is awesome',
  'Jurgen is awesome',
  'Ben is awesome', 
  'David is awesome',
]