index.js

'use strict';

const protocolRegex = /.*?irealb:\/\/([^"]*)/;
const musicPrefix = "1r34LbKcu7";
const unscramble = require('./unscramble');
const parser = require('./Parser');

function parseMusic(data) {
  const parts = data.split(musicPrefix);
  return parser(unscramble.ireal(parts[1]));
}

function makeSong(data) {
  const parts = data.split(/=+/).filter(x => x != ""); //split on one or more equal signs, remove the blanks
  let title, composer, style, key, transpose, music, compStyle, bpm, repeats = null;

  if (parts.length === 7) {
    [title, composer, style, key, music, bpm, repeats] = parts;
  }
  if (parts.length === 8 && parts[4].startsWith(musicPrefix)) {
    [title, composer, style, key, music, compStyle, bpm, repeats] = parts;
  }
  if (parts.length === 8 && parts[5].startsWith(musicPrefix)) {
    [title, composer, style, key, transpose, music, bpm, repeats] = parts;
  }
  if (parts.length === 9) {
    [title, composer, style, key, transpose, music, compStyle, bpm, repeats] = parts;
  }

  return {
    title,
    composer,
    style,
    key,
    transpose: transpose ? parseInt(transpose) : null,
    music: parseMusic(music),
    compStyle,
    bpm: bpm ? parseInt(bpm) : null,
    repeats: repeats ? parseInt(repeats) : null
  }
}

module.exports = function (data) {
  const percentEncoded = protocolRegex.exec(data);
  const percentDecoded = decodeURIComponent(percentEncoded[1]);
  const parts = percentDecoded.split("===");  //songs are separated by ===

  return {
    name: (parts.length > 1) ? parts.pop() : undefined,
    songs: parts.map(x => makeSong(x))
  }
};