custom header for day view

I’m looking to make a custom header for a day view. for example to count how many events per day and to make header like that: 01-03-2019 (8 events)

how I can make it?

[mehrdad-shokri]

Example

components={{
		week: {
			header: ({ date, localizer }) => localizer.format(date, 'dddd')
		}
}}

[josh-g3]

This isn’t working for me.