now the front end of my project is react, the back end is ssm, front end in localhost:3000, and the back end is in localhost:8080,
, that is, how to transfer the request of localhost:3000 to localhost:8080,
how to correctly set the location of nginx
the following is my location configuration:

   server { 
   listen 80; 
   
   server_name  localhost;

    -sharpcharset koi8-r;

    -sharpaccess_log  logs/host.access.log  main;

    location / {
        root   html;
        index  index.html index.htm;  
    }

    -sharperror_page  404              /404.html;

    -sharp redirect server error pages to the static page /50x.html
    -sharp
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   html;
    }

    -sharp proxy the PHP scripts to Apache listening on 127.0.0.1:80
    -sharp
    location ~ \.json$ {
        proxy_pass http://localhost:8080;
    }

    -sharp pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    -sharp
    -sharplocation ~ \.php$ {
    -sharp    root           html;
    -sharp    fastcgi_pass   127.0.0.1:9000;
    -sharp    fastcgi_index  index.php;
    -sharp    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    -sharp    include        fastcgi_params;
    -sharp}

    -sharp deny access to .htaccess files, if Apache"s document root
    -sharp concurs with nginx"s one
    -sharp
    -sharplocation ~ /\.ht {
    -sharp    deny  all;
    -sharp}
}

!!