Ideally, I'd like to create a stand-alone Angular 2 component (with tests) and then re-use it between two or three different Angular 2 sites. What are the good ways to achieve this?
And a bonus question - do any 3rd party Angular 2 components exist?
You can create an angular2 component library (with tests) and then use it in any number of projects
Here's how to create an angular2 library https://makina-corpus.com/blog/metier/2017/how-to-create-an-angular-library
Then you can publish it for public use as well. If you want to keep it private, you can read this https://www.npmjs.com/onsite
Yes, many 3rd party angular2 components exist. Here are few from valor-software https://github.com/valor-software/ng2-plans
Yeoman Generator for angular library https://github.com/jvandemo/generator-angular2-library