Implementing classes using the new ES6 syntax (branch 5.0)

[leonardo-silva]

I created a new PR to change the branches (5.0 -> 5.0).
Initial PR: #3069

Original message:
Hi,

In my PhD research, I am using express in some experiments.

As a result, I detected the existence of at least 3 main "classes" in the current codebase (View, Route, Layer).

So, I decided to rewrite this code to follow the new syntax for classes provided by ECMAScript 2016, which I think is much more readable. All changes are just syntactical. I was also very careful to preserve the code style.
Finally, all tests are green in the migrated code.

Do you think it is worth to integrate these changes to the project?

Thank you

[Twipped]

Change for change's sake 👎

[TrejGun]

why only one class? change all and add babel config to transpile to work on old nodejs, otherwise it is useless

[leonardo-silva]

It seems that classes Route and Layer were removed in branch 5.0

[dougwilson]

I'm 👎 and looks like a lot of the TSC and contributors are as well. At the very least, it causes failures on the currently-supported platforms and, as stated above, really just change for change :) To expand on that, we keep our source in ES5 to support the largest user base as is reasonable, being a core library.