We cannot parse String to different data types when it is null or blank. We get Cannot coerce string to exception.

Use default keyword to fix this issue.

Sample code:

output application/json  
---  
payload map ( payload01 , indexOfPayload01 ) -> {  
    Stree: payload01."Applicant Address Street",  
    Birthdate: payload01."Applicant Birthdate" as Date default null,  
    BorrowerId: payload01."Applicant Borrower Id" as Number default null,  
} 

If “Applicant Birthdate” is blank or null, then null is set to Birthdate.

If “Applicant Borrower Id” is blank or null, then null is set to BorrowerId.