How to create an https redirect rule for htaccess?

Question

htaccess

There is a React web application on the subdomain foo.site.ru
It is necessary that when accessing it via http, there should be a redirect to https
This redirect must be combined with the existing code (it directs all requests like foo.site.ru/page to index.html)

RewriteBase /
RewriteRule ^index\.html$ - [L]
 RewriteCond %{REQUEST_FILENAME} !-f
 RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.html [L]

Answer 1

RewriteEngine On
RewriteBase /

RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

RewriteRule ^index\.html$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.html [L]