Notes like E#, F and C#, Db are definitely not the same due to enharmonics. They only equate to the same frequency under equal temperament.

This is a duplicate of https://www.codewars.com/kata/579f54c672292dc1a20001bd

Lacks random tests

You will be given a root note as a string,

So perhaps the parameter to the function should be called root instead of chord

Tests could easily force an O(n) instead of O(n²) solution.

(I was lazy myself; I was a bit disappointed it passed the tests.)