.htaccess for one-page web apps: redirect everything except requests for filenames ending in `.png, .jpg, .gif, .jpeg, .bmp, .js, .css, or .svg` (you can add more to that list where you see those file endings)

.htaccess

<IfModule mod_rewrite.c>
  RewriteEngine On
  RewriteBase /
  RewriteRule ^index\.html$ - [L]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_URI}  !(\.png|\.jpg|\.gif|\.jpeg|\.bmp|\.js|\.css|\.svg)$
  RewriteRule ^(.*) /index.html [L]
</IfModule>