export const isNote = (name) => /^[a-gA-G][#b]?[0-9]$/.test(name); export const tokenizeNote = (note) => note.match(/^([a-gA-G])([#b])?([0-9])?$/).slice(1); export const toMidi = (note) => { const [pc, acc, oct] = tokenizeNote(note); const chroma = { c: 0, d: 2, e: 4, f: 5, g: 7, a: 9, b: 11 }[pc]; const offset = acc?.split('').reduce((o, char) => o + { '#': 1, b: -1 }[char], 0) || 0; return (Number(oct) + 1) * 12 + chroma + offset; }; export const fromMidi = (n) => { return Math.pow(2, (n - 69) / 12) * 440; };