Treat 1900 as blank in M and calculate the difference in Minutes

[v_mark]

I was trying to do this type of DAX in Power Query but no luck. 
Not sure if there is a way to achieve this in M. Please help.

Duration in Mins =
IF (
'Incident'[Stat_RepairStart] = DATE ( 1900, 1, 1 ),
BLANK (),
DATEDIFF ( 'Incident'[Stat_Diagnosis], 'Incident'[Stat_RepairStart], MINUTE )
)

[AlexisOlson · Accepted solution]

In M, you could write this as a custom column similar to this:

if [Stat_RepairStart] = #datetime(1900,1,1,0,0,0) then null
else Duration.TotalMinutes([Stat_RepairStart] - [Stat_Diagnosis])

[v_mark]

Looks like after then the null is causing an error. 

[AlexisOlson]

It's case-sensitive so you can't use If instead of if

[v_mark]

Holy cow. Didn't see that clearly. My bad. Thanks for the help! It is working