Import Javascript libraries into Angular 2

I had and still have not much experience in web engineering (Javascript, npm-Tool, …) when I started working with Angular 2. There I have a problem that normally one imports an angular-module with e.g. “import {Injectable} from '@angular/core';”. But I want to use the Javascript-library “cytoscape.js”. The problem now is, how to import it such that I can use it.
Subscribe to Cytoscape.js