JavaScript Array Iteration Methods Course (How To)

Learn how to access and transform data in arrays with JavaScript's array iteration methods. You'll learn how, why, and when to use these powerful methods to make your code easier to read and more concise.

What you'll learn

• forEach()
• filter()
• map()
• reduce()

Array Iteration

The most common action you'll need to do with arrays is to look through each of its items. This is called iteration. Let's compare two approaches to iteration: for loops and the forEach method. Then we'll take a closer look at the forEach method.

Chevron 6 steps

• JavaScript Array Overview

  3:01

• Arrays Review

  5 questions

• `for` vs forEach()

  6:53

• Examples Using forEach()

  5:08

• forEach() `index` and `array` Parameters

  2:04

• Practice forEach()

  1 objective

Array Manipulation

Learn the most common iteration methods: filter(), map(), and reduce(). Each one is a tool in your belt, and you'll see when and how to use each one.

Chevron 6 steps

• Remove Array Items with filter()

  8:45

• Practice filter()

  1 objective

• Transform Array Items with map()

  8:14

• Practice map()

  1 objective

• Return a Single Value from an Array with reduce()

  8:50

• Practice reduce()

  1 objective

Combining Array Methods

Array methods can be chained together to give you even more power in working with array data. Learn how to combine filter(), map(), and reduce() in different ways to tackle common programming problems.

Chevron 11 steps

• Chaining Array Methods

  3:37

• Method Chaining

  1 objective

• Working with Objects in Arrays

  7:40

• Working with Objects

  1 objective

• Combining filter() and map()

  4:13

• Combining filter() and map()

  1 objective

• Combining filter() and reduce()

  4:42

• Combining filter() and reduce()

  1 objective

• Nested Data and Additional Exploration

  7:25

• Array Flattening

  1 objective

• Nested Data

  1 objective