Improve Concept Exercise: Elyses Transformative Enchantments (array-transformations)

The goal of this task is to make sure the Concept Exercise “Elyses Transformative Enchantments” conform to the latest specification. As part of that, the concept array-transformations has to be created.

The docs can be found here

• What are Concept Exercises?
• Concept Exercises
• Concepts

Additionally you can look at the bird-watcher concept exercise for reference.

The improvement should include changing the introduction.md file of the exercise to contain some minimal information so that the student is able to solve the exercise. For now it is ok to use that same content as introduction.md and about.md for the Concept as well.

Also ensure that

• there are good blurbs for the concept and exercise
• the tests are declarative (see https://github.com/exercism/javascript/issues/1019 for an example)
• each test case is “self-contained” so that the student sees meaningful output from the test runner (no forEach, no helper functions defined in other parts of the test file etc.)

Here is a general idea for the introduction that was discussed before: Show how to do something like map or filter with a simple for loop, then show how to do it with the helper method instead. Afterwards provide a table with the common helpers. Just the method name as a link (e.g. to MDN) and a short explanation what this is for. We think its ok if the student reads up on some details of these methods on their own, we don’t want to show and explain every single one in detail. Also the list can contain more things, than needed for the exercise (we count that info as “necessary to understand the concept” in contrast to “necessary to solve the exercise”).

It might make sense to replace the fill task of the exercise (the last one) with reverse instead as that is probably more commonly used.

[junedev]

The array transformation concept exists now. The following tasks are left:

• Double check/improve the exercise as described above.
• Change the task that currently uses fill to instead teach reverse. Make sure to also adjust the hints, instructions etc.
• Add sort to the concept.
• Copy the concept introduction into the exercise introduction.

[junedev]

Yes, that would be great! Note that I extended the issue description with some ideas about the introduction that I discussed with DJ but forgot to write down before.