Enqueue scripts and css if not already loaded

I’m creating a custom shortcodes plugin but I have not been able to find a solution to this problem I’ve encountered…

How can I prevent my plugin’s scripts and css from being enqueued when another source like a theme or plugin already loads them, otherwise if they do not, then have my plugin will load them?

For example, Font Awesome icons are used in some of my shortcodes, but I don’t want the font awesome CSS to load if it’s already in a site from another source, otherwise the user gets two instances of it.