ViewTimeline is not defined

[ackava]

I checked the demo https://flackr.github.io/scroll-timeline/demo/view-timeline/ on both Safari and Firefox on Windows and Mac, for both browsers, the script fails with following error.

Uncaught ReferenceError: ViewTimeline is not defined
    createProgressAnimation https://flackr.github.io/scroll-timeline/demo/view-timeline/:181
    createAnimations https://flackr.github.io/scroll-timeline/demo/view-timeline/:198
    <anonymous> https://flackr.github.io/scroll-timeline/demo/view-timeline/:271