英数字のみ TextField ( "Input" , text : $input ) . onChange ( of : input , perform : filter ) func  filter ( value : String ) {         let  validCodes = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"         let  sets = CharacterSet ( charactersIn : validCodes)          input  = String (value. unicodeScalars . filter (sets. contains ). map ( Character . init ))                  if  10  < input . count  {             input  = String ( input . prefix ( 10 ))         }     } https://zenn.dev/yorifuji/articles/swiftui-textfield-filter