hands-on lab

Working With JavaScript Higher Order Functions

Up to 45m
Get guided in a real environmentPractice with a step-by-step scenario in a real, provisioned environment.
Learn and validateUse validations to check your solutions every step of the way.
See resultsTrack your knowledge and monitor your progress.


In this lab, you will be working with JavaScript Higher Order Functions. A higher order function is a function that takes another function as an argument or returns a function. You will be working with the following higher order functions that are built into Javascript:

  • Map
  • Filter
  • Reduce

Learning Objectives

Upon completion of this lab, you will be able to:

  • Use the map method to iterate over an array and return a new array with the resulting values of the operation performed on each element.
  • Use the filter method to iterate over an array and return an array with the resulting values that returned true based on the condition performed on each element.
  • Use the reduce method to iterate over an array and return the resulting singular value due to the reducer function and the initial value provided.

Intended Audience

  • Beginners learning front-end development
  • Software Engineers who need to learn front-end technologies to expand their skillset


The following content can be used to fulfill the prerequisite:

About the author

Farish Kashefinejad, opens in a new tab
Full-Stack Development Content Creator
Learning paths

Farish has worked in the EdTech industry for over six years. He is passionate about teaching valuable coding skills to help individuals and enterprises succeed.

Previously, Farish worked at 2U Inc in two concurrent roles. Farish worked as an adjunct instructor for 2U’s full-stack boot camps at UCLA and UCR. Farish also worked as a curriculum engineer for multiple full-stack boot camp programs. As a curriculum engineer, Farish’s role was to create activities, projects, and lesson plans taught in the boot camps used by over 50 University partners. Along with these duties, Farish also created nearly 80 videos for the full-stack blended online program.

Before 2U, Farish worked at Codecademy for over four years, both as a content creator and part of the curriculum experience team.

Farish is an avid powerlifter, sushi lover, and occasional Funko collector.

Covered topics

Lab steps

Introduction to JavaScript Labs
Mapping Numbers Array to Increase Element Value by One
Filter Numbers Array for Values Greater Than or Equal to Fifty
Reduce Numbers Array for Total Value of All Elements