Install the Font Awesome npm package

npm install font-awesome --save

In the .angular-cli.json file you have to add the reference to the font-awesome.css that you just installed:

	"styles": [
	  "styles.css",
	  "../node_modules/bootstrap/dist/css/bootstrap.min.css",
	  "../node_modules/font-awesome/css/font-awesome.css"
	],

In your pages you can reference the icons, e.g.:

<a href="http://twitter.com/marcomolteni" target="_blank"><i class="fa fa-twitter fa-2x menu-icon" aria-hidden="true"></i></a>

with the following result:

You can find an example in the javademo.io website:`

Here the list of the available icons http://fontawesome.io/icons/