code: function isVisualViewport ( name ) {
          var viewport = isString( name ) && name.toLowerCase();
  
          if ( name && !viewport ) throw new Error( "Invalid viewport option: " + name );
          if ( viewport && viewport !== "visual" && viewport !== "layout" ) throw new Error( "Invalid viewport name: " + name );
  
          return viewport === "visual";
      }
docs: Checks if the argument is the name of the visual viewport. The check is case-insensitive.
  
  Expects a string. Tolerates falsy values, returning false then (argument is not naming the visual viewport).
  Throws an error for everything else. Also throws an error if the viewport name is a string but not recognized
  (typo alert).
  
  Helper for getWindowQueryConfig().
  
  @param   {string} [name]  strings "visual", "layout" (case-insensitive)
  @returns {boolean}