code: function ANSIState(legacy) {
  
      var feed = '',
          last_match = '',
          stream_match = [],
          _this = this;
  
      PassThrough.call(this);
  
      this.attrs = {};
      this.reset();
      this.is_reset = false;
      this.setEncoding('utf8');
  
      this.on('data', function(chunk) {
          feed += chunk;
          if (feed.indexOf('\033') === -1) {
              feed = '';
          } else {
              stream_match = feed.match(color_regex);
              if (stream_match.length > 0) {
                  last_match = stream_match[stream_match.length - 1];
                  feed = feed.slice(feed.lastIndexOf(last_match) + last_match.length);
                  _this.updateWithArray(stream_match);
              }
          }
      });
  
      if (legacy !== undefined) {
          this.update(legacy);
      }
  }
docs: ANSI state constructor