teoria/index.js

Music theory for JavaScript

var Note = require('./lib/note');
var Interval = require('./lib/interval');
var Chord = require('./lib/chord');
var Scale = require('./lib/scale');

var teoria;

// never thought I would write this, but: Legacy support
function intervalConstructor(from, to) {
  // Construct a Interval object from string representation
  if (typeof from === 'string')
    return Interval.toCoord(from);

  if (typeof to === 'string' && from instanceof Note)
    return Interval.from(from, Interval.toCoord(to));

  if (to instanceof Interval && from instanceof Note)
    return Interval.from(from, to);

  if (to instanceof Note && from instanceof Note)
    return Interval.between(from, to);

  throw new Error('Invalid parameters');
}

intervalConstructor.toCoord = Interval.toCoord;
intervalConstructor.from = Interval.from;
intervalConstructor.between = Interval.between;
intervalConstructor.invert = Interval.invert;

function noteConstructor(name, duration) {
  if (typeof name === 'string')
    return Note.fromString(name, duration);
  else
    return new Note(name, duration);
}

noteConstructor.fromString = Note.fromString;
noteConstructor.fromKey = Note.fromKey;
noteConstructor.fromFrequency = Note.fromFrequency;
noteConstructor.fromMIDI = Note.fromMIDI;

function chordConstructor(name, symbol) {
  if (typeof name === 'string') {
    var root, octave;
    root = name.match(/^([a-h])(x|#|bb|b?)/i);
    if (root && root[0]) {
      octave = typeof symbol === 'number' ? symbol.toString(10) : '4';
      return new Chord(Note.fromString(root[0].toLowerCase() + octave),
                            name.substr(root[0].length));
    }
  } else if (name instanceof Note)
    return new Chord(name, symbol);

  throw new Error('Invalid Chord. Couldn\'t find note name');
}

function scaleConstructor(tonic, scale) {
  tonic = (tonic instanceof Note) ? tonic : teoria.note(tonic);
  return new Scale(tonic, scale);
}

teoria = {
  note: noteConstructor,

  chord: chordConstructor,

  interval: intervalConstructor,

  scale: scaleConstructor,

  Note: Note,
  Chord: Chord,
  Scale: Scale,
  Interval: Interval
};


require('./lib/sugar')(teoria);
exports = module.exports = teoria;