How to load codemirror addons ?

**Describe your question**
I'm trying to load some `addons` from the `codemirror` package, but looks like is not possible to do ?

```
import 'codemirror/addon/selection/active-line.js';
```

Start with the reported import path, `codemirror/addon/selection/active-line.js`, and reproduce the attempt to load it from EasyMDE. Trace how the codemirror package is made available, then define done as a confirmed, supported way to load the requested addon or a clear explanation of why it cannot be loaded.

Written by the indexing model from the issue text.