the secret of how to remove the .html and trailing slash on nginx without redirect loops

SLASHKILLER

   #please ignore my indenting 
   location  / {
     try_files $uri $uri/ @htmlext;
   }
   location ~ \.html$ {
        try_files $uri =404;
    }
    location @htmlext {
        rewrite ^(.*)$ $1.html last;
    }