window -> global breaks normal behavior

[Sloth-Wizard]

Issue

Upgrading to latest version of fizzy-ui-utils breaks normal behavior when bundling with parcel's latest version (2.3.2).

When building in production mode
Uncaught TypeError: e is undefined

When building in dev mode
No error but slider behaviour is wrong (see image)

As you can see dots disapeared and all slides appart from the 1st one is invisible with flickity-fade

Reproduction

npm i flickity@3.0.0
npm i flickity-as-nav-for@3.0.0
npm i flickity-fade@2.0.0
npm i --save-dev parcel@2.3.2

Then init a flickity basic slider with the fade like this

let flkty = new Flickity(cells_container, {
    lazyLoad: 3,
    wrapAround: true,
    fade : true,
    adaptiveHeight: true,
    initialIndex: -1,
    prevNextButtons: false,
    autoPlay: true
});

p.s: I have fixed the Uncaught TypeError: e is undefined when building in production by changing the this to global in fizzy-ui-utils code.

Downgrading to flickity-fade@1.0.0 fixes the issues but then you need 2 fizzy-ui-utils versions

Thanks.