CSV Parser in JS

csvparser.js

function ValueToken(value) {
  this.value = value;
}

function CommaToken() {
}

function NewLineToken() {
}

function EOFToken() {
}

function Tokenizer(data) {
  this.data = data;
  this.currentIndex = 0;
}

Tokenizer.prototype.nextToken = function() {
  if (this.currentIndex === this.data.length)
    return new EOFToken();

  var nextChar = this.data.substring(this.currentIndex, this.currentIndex + 1);

  // Comma
  if (nextChar === ',') {
    this.currentIndex++;
    return new CommaToken();
  }

  // New Line
  if (nextChar === '\n') {
    this.currentIndex++;
    return new NewLineToken();
  }

  // Quoted value
  if (nextChar === '"') {
    var nextQuoteCharIndex = this.data.indexOf('"', this.currentIndex + 1);

    if (nextQuoteCharIndex === -1)
      throw 'Unclosed quoted value.';

    value = this.data.substring(this.currentIndex + 1, nextQuoteCharIndex);
    this.currentIndex = nextQuoteCharIndex + 1;

    return new ValueToken(value);
  }

  // Value
  var nextCommaOrNewLineIndex = this.data.substr(this.currentIndex).search(/,|\n/);

  if (nextCommaOrNewLineIndex === -1) {
    var value = this.data.substring(this.currentIndex);
    this.currentIndex = this.data.length;

    return new ValueToken(value);
  }

  var value = this.data.substring(this.currentIndex, this.currentIndex + nextCommaOrNewLineIndex);
  this.currentIndex += nextCommaOrNewLineIndex;

  return new ValueToken(value);
};

function parse(data) {
  var tokenizer = new Tokenizer(data);
  var lines = [];
  var line = [];

  while (true) {
    token = tokenizer.nextToken();

    if (token instanceof ValueToken) {
      line.push(token.value);
      continue;
    }

    if (token instanceof CommaToken) {
      continue;
    }

    if (token instanceof NewLineToken) {
      lines.push(line);
      line = [];
      continue;
    }

    if (token instanceof EOFToken) {
      lines.push(line);
      break;
    }

    throw 'Unsupported token'
  }

  return lines;
}

var input = 'artist,album,year\n"Dream Theater",Octavarium,2005\n"Pink Floyd","The\nWall",1979';
console.log(parse(input));