What is the syntax for importing / using NPM modules with Angular in app.js?

Question

I use Ionic and AngularJS to create a mobile application.

I have an API that I have to use (not sure if I can say that because of stupid NDA stuff).

But the documentation requires it npm install. I am currently studying Ion, and I wonder what to do about it? How to import my API using Angular so that I can call?

Node:

var api = require('npm-api'); (This is, but in Angular.)

api.doSomething({...}); Etc ...

So basically how it looks in node. How to do it with Angular? I like Angular MV *, especially for this Ionic mobile app, so I'm wondering what is the best, most efficient way to do this.