Haskell translation

Description does not explain what are criteria for "Invalid triangle".

Given the spec below, I was surprised to get invalid length types (strings). This is just annoying.
Also, as stated in other posts, don't just assume people know what these types of triangles are.
Add more information to the description.

Build a function that will take the length of each side of a triangle 

Kata description can be improved:

isMatching checks if a string st can be created by combining and rearranging the letters of two other strings st1 and st2.

Things to be careful of:

• Spaces are ignored when checking match
• Special characters and numbers will never be present in st, but may be present in st1 and st2
• Match should be non-case sensitive.

Return true if st can be obtained from rearranging st1 and st2 following the rules above or false otherwise.

For example:

isMatching("email box", "b aIl", "Mo x e") return true

isMatching("bouh", "0b", "uh") return false

isMatching("kata", "kt", "aaa") return false

It's not explained how filenames with non-lowercase extensions should be handled exactly.

".tiff"

This is not a valid filename (it could be a hidden directory, or probably(?) a hidden file without extension). Either the description should mention such case, or this input should be removed.

Test.assertDeepEquals should be used, or better Node 10 + chai.

Javascript version of Kata should include random tests to prevent low-level cheats such as those passing in fixed values in the correct order.

would be great if you explain triangles rules, it is just to clarify kata problem

Duplicate of Roman Numerals Encoder

Filenames should be allowed to contain spaces.