refactor.js

var globals = {
	naturals:    ['C', 'D', 'E', 'F', 'G', 'A', 'B'],
	degrees:     ['R', 'm2', 'M2', 'm3', 'M3', 'P4', ['A4', 'D5'], 'P5', 'm6', 'M6', 'm7', 'M7'],
	modeNames:   ['Ionian', 'Dorian', 'Phrygian', 'Lydian', 'Mixolydian', 'Aeolian', 'Locrian'],
	accidentals: {'-1': '♭', 0: '', 1: '♯'},
	sharpScales: ['G', 'D', 'A', 'E', 'B', 'F♯'],
	flatScales:  ['F', 'B♭', 'E♭', 'A♭', 'D♭', 'G♭'],
	scales: {
		'Major':               [2, 2, 1, 2, 2, 2, 1],
		'Minor':               [2, 1, 2, 2, 1, 2, 2],
		'Harmonic Minor':      [2, 1, 2, 2, 1, 3, 1],
		'Diminished Arpeggio': [3, 3, 3, 3]
	},
};

var Scale = function() {
	this.key = null;
	this.steps = null;
	var private = {
		modulate: function(arr, offset, steps) {
			if(! Array.isArray(arr) || isNaN(offset) || (steps !== undefined && ! Array.isArray(steps))) {
				throw 'invalid paramaters to modulate()';
			}
			var count = arr.length,
				height = arr.length,
				result = [];
			if(steps !== undefined) {
				result.push(arr[offset]);
				count = steps.length;
			}
			for(var i = 0, j = 0; i < count; ++i) {
				var node = offset + (steps ? j += steps[i] : i);
				if(node >= height)
					node %= height;
				result.push(arr[node]);
			}
			return result;
		},
	};

	this.getDegrees = function() {
		if(this.steps === null) {
			throw 'Undefined scale steps';
		}
		var degrees = private.modulate(globals.degrees, 0, this.steps);
		degrees.pop();
		if(Array.isArray(degrees[3])) {
			degrees[3] = degrees[3][0];
		}else if(Array.isArray(degrees[4])) {
			degrees[4] = degrees[4][1];
		}
		return degrees;
	};

	this.keyOf = function(key) {
		this.key = key;
		return this;
	};

	this.modeOf = function(mode) {
		this.steps = private.modulate(globals.scales.Major, globals.modeNames.indexOf(mode));
		return this;
	};

	this.toArray = function() {
		if(this.key === null || this.steps === null) {
			throw 'Undefined key or scale steps';
		}
		var result = private.modulate(globals.naturals, globals.naturals.indexOf(this.key[0]));
		var append = '', useflats = true;
		if(this.key.length > 1)
			append = this.key[1];
		if(globals.sharpScales.indexOf(this.key) !== -1) {
			useflats = false;
		} else {
			useflats = true;
		}
		result = result.map(function(e) {
			//TODO: append or no?
			return e + append;
		});
		return result;
	};
};

var printModes = function(key) {
	if(key.length === 2) {
		if(key[1] == '#') {
			key = key.replace('#', globals.accidentals['1']);
		} else if(key[1] == 'b') {
			key = key.replace('b', globals.accidentals['-1']);
		}
	}
	globals.modeNames.forEach(function(mode) {
		var newScale = new Scale().keyOf(key).modeOf(mode);
		console.log(mode, newScale.getDegrees());
		console.log(newScale.toArray());
	});
};

printModes(process.argv[2]);