Best way to include external javscript

Hi there,
I’m building a simple (and my first) app that pulls info from my blog’s json resource and then display a simple list. I use ion-infinite-scroll to load more items, but the scroll speed gets affected each time. I want to use an external javascript lib called waypoints.js, but I’m not sure how to include it. I used npm install and bower install to download it into the project directory, but when I try to include it from bower_components or node_modules I get a 404 not found.

What is the best way to load external libraries into the project and still be able to update them via the CLI? I could just simply copy the javascript into the www/js folder but then I have to manually update the files in the future.