regex - htaccess remove .php, .html and trailing slash

Question

i am trying to remove .php .html and traling slash from url using htaccess,how ever this code working fine for php but not for html and trailing slash

For PHP

RewriteCond %{THE_REQUEST} ^GET.*index.php [NC]
RewriteCond %{REQUEST_URI} !/system/.* [NC]
RewriteRule (.*?)index.php/*(.*) /$1$2 [R=301,NE,L]
# Directs all EE web requests through the site index file
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php/$1 [L]

For HTML

RewriteCond %{REQUEST_URI} index.html
RewriteRule ^(.*)index.html$ /$1/ [R=301,L]

Answer 1

Have it this way:

# externally redirect /dir/file.php to /dir/file and remove index
RewriteCond %{THE_REQUEST} s/+(.*?/)?(?:index)?(.*?).(?:html?|php)/?[s?] [NC]
RewriteRule ^ /%1%2 [R=301,L,NE]

# remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{THE_REQUEST} s(.+?)/+[?s]
RewriteRule ^(.+?)/$ /$1 [R=301,L]

# internally add php extension
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/$1.php -f
RewriteRule ^(.+?)/?$ $1.php [L]

# internally add html extension
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/$1.html -f
RewriteRule ^(.+?)/?$ $1.html [L]