code: function(params) {
  
    if (!params) {
      return {
        error: 'params cannot be null.'
      };
    }
  
    // query is mandatory
    if (!params.hasOwnProperty('query')) {
      return {
        error: 'query param required.'
      };
    }
  
    if (!validator.isString(params.query)) {
      return {
        error: 'query must be a string.'
      };
    }
  
    if (!validator.isValidType(params)) {
      return {
        error: 'type must be: movie, series, episode.'
      };
    }
  
    if (params.hasOwnProperty('year') && !validator.isNumber(params.year)) {
      return { 
        error: 'year must be a valid number'
      };
    }
  
  }
docs: Validate the parameters for the search request.
  
  @param {Object} params
  @return {Object} validation state
  @api private