I always find working in Codepen a little bit annoying as you can’t have more than one javascript file except you are a pro. Is it possible to deploy the front end project codes to Heroku (as in back-end projects) and add the github link to that app page?
It would be more productive if we can have this option.
The fancy pants are also my plan too 
I wish I asked this one before I am juggling with codepen.
Also I github pages is an option too in this case if anyone comes later to this post.
By the way if you are using gulp, I can suggest you to check webpack, I recently switch to it and it is much more productive in my opinion.
I totally agree. Also it is a good experience to do code transpilings, setup your coding environment and using task runners is a crucial skill to learn anmd experiment. Codewpen takes that one away too.
Setup is just the beginning. When I was working for my last company, sharing the code was a huge problem. Many times when Mac users change something, we had issues with Windows users. For serious web development, I do believe Linux is a neccesity.
As per the Frequently Asked Questions section of About freeCodeCamp - Frequently Asked Questions :
#Do I have to use CodePen for the front end projects?
As long as your code is publicly viewable, and you have a live demo, you can use whatever you want.