NG7 - scheduler (zoom example): undefined "args" in .config ?!

I'm trying get the "zoom"-example for angular 7 up and running.

I had already the scheduler (as my NG-compnonent: "eos-scheduler") up and running fine (without the extra zoom stuff).
When I add the zoomlevel-configs to the config-property, like described in:
https://code.daypilot.org/12302/angular-scheduler-zoom

[code]
config: any = {

// ...

zoomLevels: [
{
name: "Year",
properties: {
scale: "Day",
cellWidth: 40,
timeHeaders: [{groupBy: "Year"}, {groupBy: "Month", format: "MMMM"}, {groupBy: "Day", format: "d"}],
startDate: function (args) { return args.date.firstDayOfYear(); }, //// <---- = line 203 !
days: function (args) { return args.date.daysInYear(); },
}
},
....
[/code]

I get the following error(s):

Any idea?
Thanks in advance!

JS CONSOLE Output

EosSchedulerComponent.html:3 ERROR TypeError: args.date.firstDayOfMonth is not a function
at Object.startDate [as val] (eos-scheduler.component.ts:203)
at daypilot-angular.min.js:24
at Array.forEach (<anonymous>)
at Object.zoom.Rh (daypilot-angular.min.js:24)
at Object.preInit (daypilot-angular.min.js:31)
at Object.Md [as loadOptions] (daypilot-angular.min.js:31)
at t.updateOptions (daypilot-angular.min.js:33)
at t.ngAfterViewInit (daypilot-angular.min.js:33)
at callProviderLifecycles (core.js:22318)
at callElementProvidersLifecycles (core.js:22292)