@pedroloch/tuner/dist/helpers.js

A javascript library to create a chromatic tuner that uses the ml5 pitch detection algorithm.

import { allNotes, notes } from './notes';
export function getNote(frequency) {
    // find closest frequency
    const pitch = allNotes.reduce(function (prev, curr) {
        return Math.abs(curr - frequency) < Math.abs(prev - frequency) ? curr : prev;
    });
    // find note name by closest frequency
    let note;
    if (pitch === 0)
        note = '-';
    else {
        const index = allNotes.indexOf(pitch) % 12;
        note = notes[index];
    }
    // calc diff
    const indexNote = allNotes.indexOf(pitch);
    let limit;
    const isSharp = frequency > pitch;
    if (isSharp) {
        limit = allNotes[indexNote + 1] - allNotes[indexNote];
    }
    else {
        limit = allNotes[indexNote] - allNotes[indexNote - 1];
    }
    const diff = Math.floor(((frequency - pitch) / limit) * 200);
    return { pitch, note, diff };
}