Need help inserting specific date from same row into the table

[Porkey]

I want to insert the date from row 1 into the Table on row one, the code ive used has inserted the dates as a list so they are all present. Is there a waty to get just the date from that row into the table?

Table.AddColumn(
                #"Invoked Custom Function", 
                "Custom", 
                 each Table.AddColumn(
                                       [ContentAdder],  
                                       "Date",
                                        each #"Invoked Custom Function"[Date],
                                        type date
                                       )
                )

edit: the date comes from the file name

[AlienSx]

Table.AddColumn(
    #"Invoked Custom Function", 
    "Custom", 
    (x) => 
        Table.AddColumn(
            x[ContentAdder],  
            "Date",
            (y) => x[Date],
            type date
        )
)

[edhans · Accepted solution]

You need to trap that value (date) in a variable first, then reference the variable inside the Table.AddColumn. Something like this:

Table.AddColumn(
                #"Invoked Custom Function", 
                "Custom", 

                 each 
				 	let
						varDate = [Date]
					in
					Table.AddColumn(
                                       [ContentAdder],  
                                       "Date",
                                        each varDate,
                                        type date
                                       )
                )

[Porkey]

Thank you very much. 
Can i ask why it needs to be trapped in a variable? or if you cold point me to some reading that would explain.

[edhans]

In trapping the variable the way I did, I got the value outside of the context of the next Table.AddColumn() function. You can read more about it here. M Language basic concepts - PowerQuery M | Microsoft Learn

But it is similar to using a variable in DAX to trap values at an outer context vs using EARLIER() in the inner context.