Challenges on stuff I haven't seen yet?

Do some of the FCC challenges have methods or concepts that weren’t covered previously?

I am in the middle of the ES6 portion and it asked me to use filter, map and reduce functions which I’m sure I’ve never seen before.

Which really begs the larger question, if I have no prior JS experience whatsoever, should I be taking a beginner course elsewhere before I try FCC curriculum?

I made it through html and css sections relatively easily but it seems like every other challenge in the JS section has got me completely stumped and I end up having to look at the solution to even understand what they’re asking me to do.

A lot of people here, including myself, supplement our fcc education with udemy courses.

But something else I like to do that’s free is to look up “you don’t know javascript” and read that at night, as well as go on hackerank and do every challenge in js.

Also don’t forget to google! It’s not an overnight process so if you feel like you are way in over your head, it’s a great thing.

You will learn so much more.


The javascript section does push forward in a different way than the HTML/CSS section. There is a lot of meat to javascript, and a limited number of lessons to get through it.

Javascript is also, from the student perspective, a paradigm shift – with HTML/CSS, many if not most of the answers were given to you, in the lessons at least. In the challenges, there were some hurdles, but nothing truly difficult.

With javascript, there is a lot more independent study. And this isn’t merely a factor of FCC, it really doesn’t matter where you turn to learn it. This is the beginning of true “programming”. Crafting HTML and CSS is more “design”, while javascript becomes far more programming.

So, when you see functions referred to that you don’t know, don’t default to the hints or answers. You have other tools at your disposal. A “true developer” will pop on over to the Mozilla Developer’s Network (MDN), and research each of these higher-order functions there. There is a WEALTH of information, and code samples, to be found on that site.

Also, research with other tools: is HUGE. Great reference for HTML, CSS, javascript, many libraries and frameworks, and a host of other languages (PHP, perl, Ruby, etc etc). Simply go on there, and search for map (or, if you want to get there quicker, Array functions).

The sign of a solid developer isn’t what she KNOWS. It’s does she know how to RESEARCH.


absolutely right – courses like codecademy, udemy, the odin project… there are many other options to experience and experiment with javascript.

You Don’t Know Javascript is an amazing series, and there are a wealth of phenomenal resources, free for the taking. Flavio Copes has a well-written book series, and there’s Eloquent Javascript, and many many others. I have a few dozen books on javascript alone stored in my google drive for quick reference.

Thanks guys, will dig in a little more and search around

yes, you are correct.

having just gone through this module you run into this a few times. it seems there was some house cleaning done to inject the new ES6 specification and some holes were created. as is in chess be mindful of the space left behind.

the filter, map and reduce methods are not covered until the functional program module and even there the map challenge makes references to a previous mention of map usage. but if you search for map in the FCC library you will notice that nearly all of the map challenges have been removed or point to dead links.

Another example of this is the slice() method which is introduced twice in two different modules receiving a more refined treatment in the functional programming module. The split() method is also referenced before its usage is explained in later modules.

in my opinion you can skip portions of the ES6 module and proceed through to functional programming (i.e, complete ALL the modules from regex to functional programming) then come back and complete it. you won’t skip a beat.

in fact, skipping ES6 for now you will notice a logical progression. by the time you get to functional programming concepts like callback, high order, first class and lambda will make sense. so when you see a pure function such as map() (not to mention understanding what a pure function is) you will be better prepared.

NOTE: if you save the ES6 challenges for later you should at least understand arrow functions as some challenges will sprinkle in its usage. its good to have an know how to use them.


very helpful thank you!

Thanks for this I really appreciate it. I was repeatedly looking back through old lessons perpetually thinking “how the hell did I already complete lessons on this and somehow have no recollection of them?”.

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