How to build js files in gulp?

Question

gulp.js

Guys, I don’t understand at all how the build order of js scripts works.
There are scripts to connect:

import $ from 'jquery'
import select2 from 'select2';
select2(window, $);

import FancyBox from '@fancyapps/fancybox';

import Swiper, {Scrollbar, Mousewheel, Navigation} from 'swiper';
Swiper.use([Scrollbar, Mousewheel, Navigation]);

And for some reason FancyBox connects before everyone else and because of this swears that there is no jQuery
Why is this happening? how is it treated?

Thank you!