I want to show the public holiday include in a periode of a project in the timeline view of the project dashboard,

First I got the list of holidays include in each project, here my function:

@api.depends('date_start', 'date')
def get_holiday(self):

    if self.resource_calendar_id:
        for leave_ids in self.env['resource.calendar.leaves'].search([
                                                            ('calendar_id', '=', self.resource_calendar_id.name),
                                                            ]):

                # datetime to date
                date_from = leave_ids.date_from.date()
                date_to = leave_ids.date_to.date()

                Range = namedtuple('Range', ['start', 'end'])

                r1 = Range(start=self.date_start, end=self.date)
                r2 = Range(start=date_from, end=date_to)

                latest_start = max(r1.start, r2.start)
                earliest_end = min(r1.end, r2.end)

                overlap = (earliest_end - latest_start).days + 1
                overlapping_dates = []

                if overlap > 0:

                    overlapping_dates = range(latest_start.toordinal(), earliest_end.toordinal() + 1)

                    overlapping_dates = [date.fromordinal(x) for x in overlapping_dates]

Now i've to call my function from javascript to show the result(public holiday) in the timeline view with deferent colors, How can i do that ?

Exemple: 01/01/2020 is public holiday, like this: