code: function handleError(err, getContext, lax) {
  
      var ctx = getContext();
  
      var line = ctx.line,
          column = ctx.column,
          data = ctx.data;
  
      // we receive the full context data here,
      // for elements trim down the information
      // to the tag name, only
      if (data.charAt(0) === '<' && data.indexOf(' ') !== -1) {
        data = data.slice(0, data.indexOf(' ')) + '>';
      }
  
      var message =
        'unparsable content ' + (data ? data + ' ' : '') + 'detected\n\t' +
          'line: ' + line + '\n\t' +
          'column: ' + column + '\n\t' +
          'nested error: ' + err.message;
  
      if (lax) {
        context.addWarning({
          message: message,
          error: err
        });
  
        return true;
      } else {
        throw error(message);
      }
    }
docs: Handle error.
  
  @param  {Error} err
  @param  {Function} getContext
  @param  {boolean} lax
  
  @return {boolean} true if handled