How to remove .html and add slash in the end of url - apache

Question

I have been trying to remove the .html extensions, and add a trailing slash in the end of URL bar.
I have certain instance like below
So if someone enters:
example.com -- goes to-- example.com/
example.com/index.html -- goes to - example.com/
example.com/index -- goes to -- example.com/
and
example.com/first-page.html -- goes to -- example.com/main-page/ but coming as example.com/main-page
example.com/parent-page/index.html -- goes to -- example.com/parent-page/ (working)
example.com/parent-page/child-page.html/ -- goes to -- example.com/parent-page/child-page/ but comes as example.com/parent-page/child-page
Here is my .htaccess, I want add the trailing slash at the end of url.
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^([^/]+)/$ $1.html
# Forces a trailing slash to be added
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(\.[a-zA-Z0-9]{1,5}|/)$
RewriteRule (.*)$ /$1/ [R=301,L]
Any one could please help me out, I would really appreciate it.

Answer 1

If you want to remove the .html extension from an HTML file, for example, yoursite.com/wallpaper.html to yoursite.com/wallpaper you simply have to alter the last line from the code above to match the filename
Removing Extensions .html
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.html [NC,L]
Adding a trailing slash at the end
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/$ $1.html
RewriteRule ^([^/]+)/([^/]+)/$ /$1/$2.html
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(\.[a-zA-Z0-9]{1,5}|/)$
RewriteRule (.*)$ /$1/ [R=301,L]
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