code: function LineReader(file) {
    if (typeof file === 'string') {
      this.readstream = fs.createReadStream(file);
    } else {
      this.readstream = file;
    }
    this.remainBuffers = [];
    var self = this;
    this.readstream.on('data', function (data) {
      self.ondata(data);
    });
    this.readstream.on('error', function (err) {
      self.emit('error', err);
    });
    this.readstream.on('end', function () {
      self.emit('end');
    });
  }
docs: Read stream data line by line.
  
  @constructor
  @param {String|ReadStream} file File path or data stream object.