Redirection Htaccess without a trailing slash - .htaccess

Question

I would like to redirect all URL having a trailing slash referenced by google to the new url without a trailing slash.
Example :
http://example.com/toto/ ===> to http://example.com/toto
Warning I already rewrite the rule to avoid the .html extension also !
Here is my existing code :
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.html [NC,L]
RewriteCond %{REQUEST_URI} (.+)$
RewriteRule ^ %1 [R=301,L]
</IfModule>
I got the following error :
Not Found
The requested URL /example/.html was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Answer 1

The objectif of the topic was to find a solution to make a redirection of existing URL listed by search engine like google to not lose the current SEO after making a complete refresh of the web site (Wordpress to bootstrap).
The first objective was to redirect all url trafics like http://example.com/toto/ (google) ===> to http://example.com/toto.
Unfortunatly I understood that making the reverse is more powerful to not lose my existing listing on google (sitemap & robots)
So I have decided to review all the code in order to have the following result by deleting the html extension and adding a trailing slash at the end of each url :
http://example.com/toto.html ===> to http://example.com/toto ==> http://example.com/toto/
Below is the code HTaccess that I used to make this possible :
RewriteEngine On
RewriteBase /
# To externally redirect /dir/foo.html to /dir/foo
RewriteCond %{THE_REQUEST} ^[A-Z]{3,}\s([^.]+)\.html [NC]
RewriteRule ^ %1/ [R,L]
# add a trailing slash at the end /dir/foo/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !/$
RewriteRule . %{REQUEST_URI}/ [L,R=301]
# delete the extension .html
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule ^(.*?)/?$ $1.html [L,QSA]
I have also added the code line below in each html page to enforce it :
<base href="http://example.com/">
Hoping to help any readers/coders in the same situation