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General Discussion

The definition of polyfills..

The Treehouse instructors all seem to know what polyfills are --but why, in all the contexts where they are used in the courses and the blogs doesn't anyone ever define where the term comes from?

Here's the closest I came to an explaination on the forum of what they are:

Devs have created javascript fallbacks, called polyfills that you can include in your page, to imitate the a CSS3 (or HTML5) feature that hasn't yet been implemented in all of the browsers.

..from James Barnett's answer in this forum post: https://teamtreehouse.com/forum/css-resets-modernizr-normalize

After much research I traced the term to a guy named Remy Sharp who discusses the origin of the term "polyfill" in this "What is Polyfill?" blog post:


Note: At the top of the blog post he says it came to him a a coffee shop that polyfill term (meaning I guess "Many Filler") could mean:

replicate an API using JavaScript (or Flash or whatever) if the browser doesn't have it natively.

so here's his definition:

A polyfill, or polyfiller, is a piece of code (or plugin) that provides the technology that you, the developer, expect the browser to provide natively.

But if you read down a little further you'll find he also made up the term because there is a brand of spackling paste called the product "Polyfilla" that can be put in to walls to cover cracks and holes.

Thus the analogy:

...think of the browsers as a wall with cracks in it. These polyfills help smooth out the cracks and give us a nice smooth wall of browsers to work with.

Oh, and here's another forum quote on polyfills from Kevin Korte:

First, yes, polyfills should be avoided if possible.

..from this forum post:


Sorry, Kevin, but I'm going to use them every chance I get!

2 Answers

..and you may be wondering:

What brought this up?

Actually it was this Treehouse Blog post:


This was an extremely hard blog post to find!


Because I was searching for: twisty triangles !

Not once did they mention "twisty" and they only mentioned "triangle" once:

By default, the browser will display a small marker triangle to the left of the summary text that indicates the current state of the <details> element.

However it did lead me to this list of polyfill javascript for twisty triangles:


These polyfills may come in handy as I'm trying to come up with a cross browser friendly version of my portfolio site...

Question of the day:

I really don't know why treehouse doesn't use use these on it's homepage

(that also functions as a personalized "to do" dashboard for Treehouse members when they are signed in),

to allow members to collapse the to do list to only the parts they want to be reminded of..

However, I'm definitely not in "sync" with the thinking of the Treehouse people..

--which you will clearly see if you read this other forum post:


Oh, I just discovered the full list of forum contests (now discontinued) under the "featured" tab at the top of the forum.

Some of the forum contest posts have a link to the next one.

Why didn't they provide a backward link (to the previous one).

In programming there are some things called "linked lists" that provide such a chaining.

Why wasn't it obvious to some of the developers at Treehouse that this would be useful?

Why? Why? Why!

I guess I'm just tormenting myself trying to understand why Treehouse content produces spent so much time generating content and so little time interlinking said content so students can research things in different ways.

Should I suggest that Treehouse courses and other content make use of
Dewey Decimal call numbers?

I should be pummeled unmercifully for even thinking such a thing...

You might as well ask them to fix the Treehouse Leaderboard page:


..which says "Home" in my Firefox tab instead of "Leaderboard"

I guess because the page source has:

<title>Treehouse | Home</title>

..instead of:

<title>Treehouse | Leaderboard</title>