Answers for "JSX not allowed in files with extension globally"

remove port ufw

$ sudo ufw status numbered
Status: active

     To                         Action      From
     --                         ------      ----
[ 1] Apache Full                ALLOW IN    Anywhere                  
[ 2] OpenSSH                    ALLOW IN    Anywhere                  
[ 3] Apache Full (v6)           ALLOW IN    Anywhere (v6)             
[ 4] OpenSSH (v6)               ALLOW IN    Anywhere (v6)

$ sudo ufw delete 3
Deleting:
 allow 'Apache Full'
Proceed with operation (y|n)? y
Rule deleted (v6)

ufw allow port

sudo ufw allow http
sudo ufw allow 80

JSX not allowed in files with extension '.js'

"rules": {
  "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
}