validate-note/src/lib/convertFlatToSharp.js

🎼 Validates a note (scientific pitch notation) and throws errors if needed

// @flow

import notes from '../data/notes';

type result = {
  signature: string,
  letter: string
};

export default (letter: string, signature: string): result => {

  signature = `#`;
  letter = notes[notes.indexOf(letter) - 1].charAt(0);

  return {signature, letter};

};