tonal-note/build/es6.js

Parse and manipulate music notes in scientific notation

var NAMES = "C C# Db D D# Eb E F F# Gb G G# Ab A A# Bb B".split(" ");
var names = function (accTypes) {
    return typeof accTypes !== "string"
        ? NAMES.slice()
        : NAMES.filter(function (n) {
            var acc = n[1] || " ";
            return accTypes.indexOf(acc) !== -1;
        });
};
var SHARPS = names(" #");
var FLATS = names(" b");
var REGEX = /^([a-gA-G]?)(#{1,}|b{1,}|x{1,}|)(-?\d*)\s*(.*)$/;
function tokenize(str) {
    if (typeof str !== "string")
        str = "";
    var m = REGEX.exec(str);
    return [m[1].toUpperCase(), m[2].replace(/x/g, "##"), m[3], m[4]];
}
var NO_NOTE = Object.freeze({
    pc: null,
    name: null,
    step: null,
    alt: null,
    oct: null,
    octStr: null,
    chroma: null,
    midi: null,
    freq: null
});
var SEMI = [0, 2, 4, 5, 7, 9, 11];
var properties = function (str) {
    var tokens = tokenize(str);
    if (tokens[0] === "" || tokens[3] !== "")
        return NO_NOTE;
    var letter = tokens[0], acc = tokens[1], octStr = tokens[2];
    var p = {
        letter: letter,
        acc: acc,
        octStr: octStr,
        pc: letter + acc,
        name: letter + acc + octStr,
        step: (letter.charCodeAt(0) + 3) % 7,
        alt: acc[0] === "b" ? -acc.length : acc.length,
        oct: octStr.length ? +octStr : null,
        chroma: 0,
        midi: null,
        freq: null
    };
    p.chroma = (SEMI[p.step] + p.alt + 120) % 12;
    p.midi = p.oct !== null ? SEMI[p.step] + p.alt + 12 * (p.oct + 1) : null;
    p.freq = midiToFreq(p.midi);
    return Object.freeze(p);
};
var memo = function (fn, cache) {
    if (cache === void 0) { cache = {}; }
    return function (str) { return cache[str] || (cache[str] = fn(str)); };
};
var props = memo(properties);
var name = function (str) { return props(str).name; };
var pc = function (str) { return props(str).pc; };
var isMidiRange = function (m) { return m >= 0 && m <= 127; };
var midi = function (note) {
    if (typeof note !== "number" && typeof note !== "string") {
        return null;
    }
    var midi = props(note).midi;
    var value = midi || midi === 0 ? midi : +note;
    return isMidiRange(value) ? value : null;
};
var midiToFreq = function (midi, tuning) {
    if (tuning === void 0) { tuning = 440; }
    return typeof midi === "number" ? Math.pow(2, (midi - 69) / 12) * tuning : null;
};
var freq = function (note) { return props(note).freq || midiToFreq(note); };
var L2 = Math.log(2);
var L440 = Math.log(440);
var freqToMidi = function (freq) {
    var v = (12 * (Math.log(freq) - L440)) / L2 + 69;
    return Math.round(v * 100) / 100;
};
var chroma = function (str) { return props(str).chroma; };
var oct = function (str) { return props(str).oct; };
var LETTERS = "CDEFGAB";
var stepToLetter = function (step) { return LETTERS[step]; };
var fillStr = function (s, n) { return Array(n + 1).join(s); };
var numToStr = function (num, op) {
    return typeof num !== "number" ? "" : op(num);
};
var altToAcc = function (alt) {
    return numToStr(alt, function (alt) { return (alt < 0 ? fillStr("b", -alt) : fillStr("#", alt)); });
};
var from = function (fromProps, baseNote) {
    if (fromProps === void 0) { fromProps = {}; }
    if (baseNote === void 0) { baseNote = null; }
    var _a = baseNote
        ? Object.assign({}, props(baseNote), fromProps)
        : fromProps, step = _a.step, alt = _a.alt, oct = _a.oct;
    if (typeof step !== "number")
        return null;
    var letter = stepToLetter(step);
    if (!letter)
        return null;
    var pc = letter + altToAcc(alt);
    return oct || oct === 0 ? pc + oct : pc;
};
var build = from;
function fromMidi(num, sharps) {
    if (sharps === void 0) { sharps = false; }
    num = Math.round(num);
    var pcs = sharps === true ? SHARPS : FLATS;
    var pc = pcs[num % 12];
    var o = Math.floor(num / 12) - 1;
    return pc + o;
}
var simplify = function (note, sameAcc) {
    if (sameAcc === void 0) { sameAcc = true; }
    var _a = props(note), alt = _a.alt, chroma = _a.chroma, midi = _a.midi;
    if (chroma === null)
        return null;
    var alteration = alt;
    var useSharps = sameAcc === false ? alteration < 0 : alteration > 0;
    return midi === null
        ? pc(fromMidi(chroma, useSharps))
        : fromMidi(midi, useSharps);
};
var enharmonic = function (note) { return simplify(note, false); };

export { names, tokenize, props, name, pc, midi, midiToFreq, freq, freqToMidi, chroma, oct, stepToLetter, altToAcc, from, build, fromMidi, simplify, enharmonic };