code: function(json, fields) {
      if (((typeof json) === 'object') && !Array.isArray(json))
        return hasFields(json,fields);
      else if (Array.isArray(json)) {
        var spliced = [];
        var n = json.length;
        while (n--)
          if (hasFields(json[n],fields))
            spliced.push(json[n]);
  
        if (spliced.length)
          return spliced;
        else
          return false;
      }
      else
        return console.error(new Error('Bad data passed to clean.forFields()'));
    }
docs: removes texts that don't have the specified fields