I'm a bit confused about modern frontEnd architecture/folder organisation.

In all the most popular frameworks (angular, react, vue), I see the following:

```
/src
----/app
----app.main.js
index.js

```

**index.js** is the entry point of the application, is the file where our app is bootstrapped.

**app.main.js** is the *real* entry point of our app.

Let's say I have some global variables to define or third part libraries to include (js & css).

Where should I import them?