note-to-frequency/cjs/index.js

🎼 converts a note (scientific pitch notation) to a frequency

'use strict';

exports.__esModule = true;

var _validateNote2 = require('validate-note');

var _validateNote3 = _interopRequireDefault(_validateNote2);

var _getPosition = require('./lib/getPosition');

var _getPosition2 = _interopRequireDefault(_getPosition);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

exports.default = function (note) {
  var _ref = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {},
      _ref$base = _ref.base,
      base = _ref$base === undefined ? 440 : _ref$base,
      _ref$maxOctave = _ref.maxOctave,
      maxOctave = _ref$maxOctave === undefined ? 8 : _ref$maxOctave;

  var _validateNote = (0, _validateNote3.default)(note, {
    flatToSharp: true,
    maxOctave: maxOctave,
    octave: true
  }),
      letter = _validateNote.letter,
      octave = _validateNote.octave,
      signature = _validateNote.signature;

  var pos = (0, _getPosition2.default)(letter, octave, signature);
  var basePos = (0, _getPosition2.default)('A', 4);
  var diff = pos - basePos;

  var a = Math.pow(2, 1 / 12);
  return Math.round(base * Math.pow(a, diff) * 100) / 100;
};

module.exports = exports['default'];